Systems and methods for implementing haptics for pressure sensitive keyboards

ABSTRACT

Systems and methods are employed for implementing haptics for pressure sensitive keyboards, such as the type of keyboards having keys that produce alternating digital open/short signals that emulate actuation of conventional “momentary on” digital keys. The disclosed systems and methods may be implemented to provide haptics for both touch typing and variable pressure sensitive operation of a pressure sensitive keyboard. Users of a variable pressure keyboard may be provided with a variable pressure haptics effect, e.g., to enable the user to intuitively understand from the haptics vibration produced by the key how much pressure they are applying to a given key at any given time. Vibration characteristics (e.g., vibration rate, vibration waveform pattern, etc.) of a given pressed key may be varied in real time in coordination with, or in response to, corresponding changes in user pressure applied to the same given key.

RELATED APPLICATIONS

This application is a continuation of pending U.S. patent applicationSer. No. 12/930,125, filed on Dec. 29, 2010 and entitled “Systems AndMethods For Implementing Haptics For Pressure Sensitive Keyboards”,which itself is a continuation-in-part of U.S. patent application Ser.No. 12/802,468, titled “Systems And Methods For Implementing PressureSensitive Keyboards,” by Mark A. Casparian, et al., filed on Jun. 8,2010, which itself is a continuation-in-part of U.S. patent applicationSer. No. 12/316,703, titled “Keyboard With User Configurable GranularityScales For Pressure Sensitive Keys,” by Mark A. Casparian, et al., filedon Dec. 16, 2008, the entire disclosure of each of the foregoingapplications being incorporated herein by reference.

TECHNICAL FIELD

The techniques described herein relate to systems and methods forkeyboards and, more particularly, for implementing haptics for variablepressure sensitive keyboards.

BACKGROUND

As the value and use of information continues to increase, individualsand businesses seek additional ways to process and store information.One option available to users is information handling systems. Aninformation handling system generally processes, compiles, stores,and/or communicates information or data for business, personal, or otherpurposes thereby allowing users to take advantage of the value of theinformation. Because technology and information handling needs andrequirements vary between different users or applications, informationhandling systems may also vary regarding what information is handled,how the information is handled, how much information is processed,stored, or communicated, and how quickly and efficiently the informationmay be processed, stored, or communicated. The variations in informationhandling systems allow for information handling systems to be general orconfigured for a specific user or specific use such as financialtransaction processing, airline reservations, enterprise data storage,or global communications. In addition, information handling systems mayinclude a variety of hardware and software components that may beconfigured to process, store, and communicate information and mayinclude one or more computer systems, data storage systems, andnetworking systems.

Many information handling systems use keyboards to obtain user input.Some prior keyboard solutions have provided pressure sensitive keys. Themost common technique to provide pressure sensitive keys is to usevariable resistance sensing techniques to provide an indication of thepressure applied by a user to a key. Variable capacitance sensing hasalso been utilized in some prior art products such as console gamepadcontrollers.

Haptics of conventional keyboards rely on the collapse of a rubber dometo provide the physical “click” sensation felt during the makeconnection. This is what keyboard users are accustomed to feeling usingconventional standard keyboards while touch typing. Conventionalvariable pressure sensitive keyboards have also employed a standardrubber dome style key mechanism that incorporates the conventional touchtype of haptics. Once a user provides enough finger force to provide the“make connection” (or collapse of the rubber dome) the finger isbottomed out against the back surface of the keyboard housing. At thispoint, as the user provides additional finger pressure, the circuitryreacts accordingly by auto-typing at a speed corresponding to the amountof force applied.

A full size USB peripheral keyboard has been developed that employs theuse of a standard rubber dome style key mechanism. This keyboardincorporates the touch typing haptics provided by conventional rubberdome keyboard solutions. Once a user provides enough finger force toprovide the “make connection” or collapse of the rubber dome, thebottom-side of the rubber dome is pressed against the back surface ofthe keyboard housing. At this point, as the user provides additionalfinger pressure, the circuitry reacts accordingly by auto-typing at avariable speed corresponding to the amount of force applied.

Force feedback game controllers on the market today incorporate feedbackvia piezo motors that have an off-center weight attached to the spindle.When the piezo motor is spinning, this offset weight produces avibration that shakes the entire game controller device. Touch screens,such as found on some conventional cellphones and smartphones, employthe use of piezo transducers to vibrate the entire screen of the deviceto provide the user feedback as to when they are touching. Hapticscontrollers are available that provide the ability to store multiplevibration waveforms and allow a user to select and output any onewaveform at a time.

SUMMARY

Systems and methods are disclosed herein for implementing haptics forvariable pressure sensitive keyboards, such as the type of keyboardshaving variable pressure sensitive keys that produce alternating digitalopen/short signals that emulate actuation of conventional “momentary on”digital keys. The disclosed systems and methods may be implemented toprovide haptics for both touch typing and variable pressure sensitiveoperation of a variable pressure sensitive keyboard. In one embodiment,the disclosed systems and methods may be implemented to provide users ofa variable pressure keyboard with a variable pressure haptics effect,e.g., to enable the user to intuitively understand from the hapticsvibration produced by the key how much pressure they are applying to agiven key at any given time. For example, vibration characteristics(e.g., vibration rate, vibration waveform pattern, etc.) of a givenpressed key may be varied in real time in coordination with, or inresponse to, corresponding changes in user pressure applied to the samegiven key. In one embodiment, each haptics-enabled key of the keyboardmay be provided with a respective haptics actuator (e.g., piezotransducer) that is configured to independently impart a haptics motion(e.g., vibration) only to the corresponding single key without impartinga user-detectable haptics motion to any other keys (including adjacentkeys) of the keyboard or to the remainder of the keyboard itself. In oneembodiment, a variable intensity haptics motion may be imparted to apressed key of a variable pressure sensitive keyboard such that thepressed key moves (e.g., vibrates with a subtle “ticking” of the keycapfelt by the finger) with a relative intensity that corresponds to theamount of pressure applied by the user's finger to the particularpressed key.

In another embodiment, the disclosed systems and methods may beimplemented to provide a keyboard that includes both momentary-on (e.g.,digital) keys and variable pressure-sensing (e.g., analog) keys in amanner such that both the momentary-on keys and the variablepressure-sensing keys feel the same when pressed by a user (i.e., bothtypes of keys have the same force/displacement curve). In such anembodiment, a mixed keyboard of momentary-on and variablepressure-sensing keys may be implemented that provides a traditionaltouch-typing feel to users across the keys of the keyboard. In yetanother embodiment, signal processing for haptics and pressure-sensitivekey toggling may be performed in parallel paths to reduce the latencyfrom finger press to resulting key vibration and toggling (i.e.,resulting letters typed on computer display). Further, the hapticswaveform address may be written to require a reduced number of clockcycles than otherwise required, e.g., such as when using I2C-basedcommunications. The disclosed systems and methods may be implementedboth for full size external/peripheral keyboards, and for notebookkeyboard arrays which are focused on thin profiles (minimal Z height).

In one embodiment, the disclosed systems and methods may be implementedto provide haptics for one or more individual variable pressuresensitive keys of keyboards that are implemented using variablecapacitance, variable conductance, variable resistance or other suitablepressure sensitive measurement methodology to generate an alternatingopen/short digital signal representative of the amount of pressureapplied to a given key at any given time. In the implementation of suchkeyboards, the open/short digital signal may be supplied as a signalrepresentative of applied key pressure to a legacy keyboard controlleror other processing device of an information handling system that isconfigured to measure keyboard input based on “momentary-on” signals. Inone exemplary embodiment, the disclosed systems and methods may beadvantageously implemented to provide a drop-in “replacement” keyboardfor a standard-type momentary-on keyboard of an information handlingsystem, e.g., portable information handling system such as a notebookcomputer that employs a conventional keyboard controller configured toreceive momentary-on digital key signals and no analog keyboard signals.Other examples of portable information handling system include, but arenot limited to, MP3 players, portable data assistants, cellular phones,tablet computers, etc.

The disclosed systems and methods may be implemented in one exemplaryembodiment to achieve fast response time and/or for interfacing with alegacy keyboard controller. In this regard, pressure-sensing digitaloutput circuitry, haptics actuation circuitry (e.g., piezo transducercircuitry) and related haptics control circuitry (e.g., includingcontroller, microcontroller, or other processing device/s) may beimplemented in a manner that supports any number of pressure sensitivekeys, is compatible with a legacy keyboard controller and devicedrivers, and using little additional power.

In one exemplary embodiment, falling edge-triggered digital interruptinputs may be provided to a processing device of pressure-sensingdigital output circuitry rather than feeding analog signals to an ADC.This advantageously allows improved response time to a user's input(e.g., finger pressure). Further, circuitry may be provided in anotherexemplary embodiment to interface any number of variable pressuresensitive keys to a legacy keyboard (e.g., 8 bit microcontroller, and 24bit interface to a legacy keyboard matrix). Low power capability may beprovided by using pressure-sensing digital output circuitry thatprocesses code in an interrupt service routine (ISR) whenever aninterrupt due to application of pressure on a pressure-sensitive key issensed on any of the digital inputs of the circuitry, and then goes tosleep (i.e., low power state) while it continues to actively monitor itsinterrupt digital inputs for any other event. Haptics controllercircuitry may also be provided that remains in low power sleep modebetween variable key press events. Thus, the pressure-sensing digitaloutput circuitry and haptics controller circuitry only monitor triggerevents, run code when trigger events are detected, and then go back tosleep again until another trigger event is detected. This translatesinto ultra low power consumption for this embodiment, which isadvantageous for “drop-in replacement” keyboard arrays that are capableof operating on an existing information handling system power supply.

Advantageously, the disclosed systems and methods may be implemented inanother embodiment to provide a “drop-in replacement” of a currentproduction keyboard array for an information handling system such as anotebook computer (e.g., for build-to-order specification, after marketreplacement in an existing previously built information handling system,updated production run, etc.) without requiring any mechanical,electrical, device driver or operating system (OS) changes to theexisting information handling system. In such an embodiment, thepressure sensitive keys, pressure-sensing digital output circuitry,haptics actuation circuitry and haptics control circuitry may beintegrated into a replacement keyboard assembly that is mechanically andelectrically compatible with the information handling system hostequipment (e.g., including legacy keyboard controller), and using nativeOS keyboard drivers to operate the keyboard. The disclosed systems andmethods may also advantageously be implemented in one embodiment toprovide variable pressure-sensitive and haptics key capability for usewith older games that only accept user key toggling because no specialcode patches are required to allow applications running on a hostinformation handling system to understand keyboard input from thevariable pressure sensitive keys of the disclosed keyboard systems,i.e., the keyboard input to the game is understood by the game as inputfrom a legacy USB keyboard.

The disclosed variable pressure sensitive keyboard measurement methodsand systems may be optionally implemented in one exemplary embodimentwith user configurable haptics-enabled variable pressure sensitive keysand techniques for controlling these keys for keyboards. In such anembodiment, user configuration information, including information foruser configurable granularity scales and/or haptics vibration waveforms,can be communicated from a host system to the keyboard and stored forlater use by a keyboard controller or other processing device associatedwith the keyboard to control the operation of the pressure sensitivekeys. Alternatively, such user configuration information may be employedby a software application operating on the host system that communicateswith a keyboard controller to control the operation of the pressuresensitive keys. Either way, greater control of the pressure sensitivekeys and/or haptics vibration of these keys can be provided. Thisconfigurability is of particular use for applications such as where thekeyboard is being used for gaming by a user running a gaming applicationon an information handling system. In particular, the user can configurethe granularity scale and/or haptics waveforms for each pressuresensitive key so that each key can provide a desired gaming response. Inaddition, different configuration files can be stored so that a user canselect and use different configurations for different games and/ordifferent users can select and use different configurations based upontheir personal preferences.

In one respect, disclosed herein is a keyboard system, including: one ormore pressure sensitive keys configured to provide analog output signalscorresponding to each given one of the pressure sensitive keys that isrepresentative of the level of pressure applied to the given key;pressure sensing interface circuitry coupled to receive the analogoutput signal from each given one of the pressure sensitive keys, thepressure-sensing digital output circuitry being configured to providekey pressure indication signals representative of at least tworespective different levels of pressure applied to the correspondinggiven one of the pressure sensitive keys, the at least two differentlevels of pressure including at least first and second different levelsof pressure; and haptics actuation circuitry coupled and configured toimpart a variable haptics motion characteristic independently to eachgiven one of the pressure sensitive keys based at least in part on thekey pressure indication signals provided by the pressure sensinginterface circuitry corresponding to the pressure level applied to thecorresponding given one of the pressure sensitive keys such that a firsthaptics motion is imparted to a given one of the pressure sensitive keysat the first pressure level applied to the given one of the pressuresensitive keys that is different than a second haptics motion that isimparted to the given one of the pressure sensitive keys at the secondpressure level applied to the given one of the pressure sensitive keys.

In another respect, disclosed herein is a method of imparting hapticsmotion, including: providing one or more pressure sensitive keys;producing an analog output signal for each given one of the pressuresensitive keys when depressed by a user, the analog output signals beingrepresentative of the level of pressure applied to the given pressuresensitive key by the user; providing one or more key pressure indicationsignals based upon the analog output signal, the one or more keypressure indication signals being representative of at least tworespective different levels of pressure applied to the given pressuresensitive key by the user, the at least two different levels of pressureincluding at least first and second different levels of pressure; andimparting a variable haptics motion characteristic independently to eachgiven one of the pressure sensitive keys based at least in part on aprovided key pressure indication signal that is representative ofpressure applied to the given pressure sensitive key by the user suchthat a first haptics motion is imparted to the given one of the pressuresensitive keys at the first pressure level applied to the given one ofthe pressure sensitive keys that is different than a second hapticsmotion that is imparted to the given one of the pressure sensitive keysat the second pressure level applied to the given one of the pressuresensitive keys.

DESCRIPTION OF THE DRAWINGS

It is noted that the appended drawings illustrate only exampleembodiments of the techniques described herein and are, therefore, notto be considered limiting of its scope, for the invention may admit toother equally effective embodiments.

FIG. 1 is a block diagram illustrating a keyboard system according toone exemplary embodiment of the disclosed systems and methods.

FIG. 2A is a diagram for a structure having both a haptics-enabledanalog key and a digital key according to one exemplary embodiment ofthe disclosed systems and methods.

FIG. 2B illustrates a haptics transducer assembly according to oneexemplary embodiment of the disclosed systems and methods.

FIG. 2C illustrates a haptics transducer configuration according to oneexemplary embodiment of the disclosed systems and methods.

FIG. 2D is a diagram for a structure having both an analog key and adigital key according to one exemplary embodiment of the disclosedsystems and methods.

FIG. 2E is a diagram for a structure having a haptics-enabled analog keyaccording to one exemplary embodiment of the disclosed systems andmethods.

FIG. 2F illustrates a haptics-enabled keycap assembly according to oneexemplary embodiment of the disclosed systems and methods.

FIG. 2G illustrates a haptics-enabled keycap assembly according to oneexemplary embodiment of the disclosed systems and methods.

FIG. 2H illustrates a haptics-enabled keycap assembly according to oneexemplary embodiment of the disclosed systems and methods.

FIG. 2I illustrates a haptics-enabled keycap assembly according to oneexemplary embodiment of the disclosed systems and methods.

FIG. 3A is a diagram for different depressed states for a half-domestructure according to one exemplary embodiment of the disclosed systemsand methods.

FIG. 3B is a diagram for a top view of the capacitive contacts for thehalf-dome structure according to one exemplary embodiment of thedisclosed systems and methods.

FIG. 4A is a block diagram illustrating a keyboard system according toone exemplary embodiment of the disclosed systems and methods.

FIG. 4B illustrates haptics control circuitry and other associatedcircuitry according to one exemplary embodiment of the disclosed systemsand methods.

FIG. 4C illustrates haptics control circuitry and other associatedcircuitry according to one exemplary embodiment of the disclosed systemsand methods.

FIG. 4D illustrates haptics control circuitry and other associatedcircuitry according to one exemplary embodiment of the disclosed systemsand methods.

FIG. 5 illustrates methodology for initialization of pressure-sensingdigital output circuitry according to one exemplary embodiment of thedisclosed systems and methods.

FIG. 6A illustrates a first portion of methodology for initialization ofhaptics control circuitry, sensing pressure applied to keys, producing atoggled digital signal representative thereof, and inducing hapticsmotion in a pressed key according to one exemplary embodiment of thedisclosed systems and methods.

FIG. 6B illustrates a second portion of methodology for initializationof haptics control circuitry, sensing pressure applied to keys,producing a toggled digital signal representative thereof, and inducinghaptics motion in a pressed key according to one exemplary embodiment ofthe disclosed systems and methods.

FIG. 7 illustrates a haptics vibration waveform according to oneexemplary embodiment of the disclosed systems and methods.

FIG. 8 illustrates a haptics vibration waveform according to oneexemplary embodiment of the disclosed systems and methods.

FIG. 9 illustrates a haptics vibration waveform according to oneexemplary embodiment of the disclosed systems and methods.

FIG. 10 illustrates a haptics vibration waveform according to oneexemplary embodiment of the disclosed systems and methods.

DETAILED DESCRIPTION OF THE INVENTION

For purposes of this disclosure, an information handling system mayinclude any instrumentality or aggregate of instrumentalities operableto compute, classify, process, transmit, receive, retrieve, originate,switch, store, display, manifest, detect, record, reproduce, handle, orutilize any form of information, intelligence, or data for business,scientific, control, or other purposes. For example, an informationhandling system may be a personal computer, a server computer system, anetwork storage device, or any other suitable device and may vary insize, shape, performance, functionality, and price. The informationhandling system may include random access memory (RAM), one or moreprocessing resources such as a central processing unit (CPU) or hardwareor software control logic, ROM, and/or other types of nonvolatilememory. Additional components of the information handling system mayinclude one or more disk drives, one or more network ports forcommunicating with external devices as well as various input and output(I/O) devices, such as a keyboard, a mouse, and a video display. Theinformation handling system may also include one or more buses operableto transmit communications between the various hardware components.

As described herein, systems and methods are provided to implementhaptics for one or more individual keys of an information handlingsystem keyboard (e.g., such as a variable pressure sensitive keyboard)using haptics actuation circuitry (e.g., such as piezo transducercircuitry) that is controlled by haptics control circuitry. For example,the solutions described herein may be employed to enable haptics forkeyboard keys including those keys used in variable pressure sensitivekeyboards such as described in U.S. patent application Ser. No.12/316,703 filed Dec. 16, 2008, and U.S. patent application Ser. No.12/802,468 filed Jun. 8, 2010, each of which is incorporated herein byreference in its entirety for all purposes. Such variable pressuresensitive keyboards may be employed, for example, in gaming applicationsand information handling systems that are specifically designed forgaming applications. However, the disclosed systems and methods areuseful for any other keyboard applications in which variable pressuresensitive keys may be employed.

As further described herein, haptics may be provided for pressuresensitive keys that produce a digital open/short signal that isrepresentative of the amount of pressure applied to a given key at agiven time. Conventional keyboards typically use rubber dome based keysthat provide a momentary-on switch contact via a make-or-break contactwith two layers of flex PCB (printed circuit board) with a raw exposedconductor pad on both layers that come into contact with one anotherupon a key press. In gaming applications, gamers typically use the W, A,S, and D keys for travel movements (forward, left, backward, rightrespectively); Q and E keys are typically used for strafing left andright respectively; and the spacebar key is used for jumping, althoughgaming keys are not restricted to these particular keys or functions.Rather than tapping a button a few times to make a gradual turn, orseveral rapid taps to make a sharp turn, it is more natural for a userto apply more pressure on the A or D keys to pull a tighter turn and/orturn with gradual or sharpness of turn desired proportionally to theamount of finger pressure applied to the respective keyboard key. Suchcapability is not only more intuitive, but allows the user easiergranular control over game play input such as gradually turning/sharpturn, variable speed of travel movement (slow walk, spring), the rate offire of a gun, variable degree of the amount of strafing to the left orright, but not limited to these examples. The advantageous solutionsdescribed herein enable haptics to be employed in one embodiment withvariable capacitance measurement for implementing pressure sensitivekeys, and may be optionally implemented with user configurablegranularity scales for these pressure sensitive keys to allow enhanceduser control of how keys respond in a gaming application and/or anyother desired application. Further information on the use of userconfiguration information, such as user configurable granularity scales,may be found in U.S. patent application Ser. No. 12/316,703 filed Dec.16, 2008, which is incorporated herein by reference in its entirety.

There are many kinds of game genres. The features and ways to utilizevariable pressure control vary from game to game or from genre to genre.For example, in a first person shooter (FPS) game, a particular variablepressure button may be used to control the speed of fire (single shot,multiple shots, faster multiple shots, machine gun rapid fire). Forreal-time strategy games, the variable finger pressure sensitivity ofthe key may mean something completely different. With a variety of gamegenres, and even within a particular genre, there are many game titles,where the user will want to save their keyboard's pressure sensitivebutton definitions and/or haptics waveform motion characteristics in aprofile for the game, even with the ability to categorize by game genre.It is also desirable to allow the user to configure how the pressuresensitive button and haptics waveform motion should work. For example,the user may want the full range of gradual variable control. In anotherinstance, the user may want this button to act like a momentary on/offswitch button. In still another instance, the user may want the buttonto operate as four (4) possible positions (e.g., slow walk, fast walk,jog, sprint) depending on the amount of pressure applied by the finger.This user configuration information, and this user configurablegranularity control in particular, as described below, can becommunicated to and stored by the keyboard to provide the user thiscapability of configuring how the keyboard pressure sensitive keysand/or haptics waveform motion for individual keys will operate.

The keyboard embodiments described herein may have from one to all oftheir keys controlled via pressure-sensitive sensors (e.g., such asvariable impedance or variable capacitance sensors), and/or may beprovided with corresponding haptics control circuitry and hapticsactuation circuitry for one or more of the individual variable pressuresensitive keys of the keyboard. As described in more detail below, aninjection molded rubber dome sheet and flex circuitry can be used, inone exemplary embodiment, to accommodate both pressure sensitive keysand traditional momentary-on switch based keys, and any one or more ofwhich keys may also include haptics actuation circuitry.

For example, using the disclosed systems and methods, a typical 24-bitdigital pathway can be used from the keyboard array to the keyboard'smicrocontroller for any momentary-on keys. Typically, a keyboardmicrocontroller has three dedicated 8-bit digital input ports to take inthis data, though it need not be limited to this. Current keyboards userubber-dome momentary-on switches. The keycap has a rod or “chimneystack” on its bottom side. There is also a nipple or actuator on thebottom side of the rubber dome. As the user presses down on the keycap,the chimney stack presses down on the rubber dome, which in turn pressesthe nipple/actuator down on the flex circuitry beneath it. This pressingmotion brings flex circuitry from one signal layer in direct contactwith flex circuitry in a second signal layer. As a result, the twoconnections make contact, signaling to the microcontroller that the keyhas been pressed (the momentary-on signal). These rubber-domemomentary-on switches can be used for the non-pressure sensitive keysfor the keyboards described herein.

In one exemplary embodiment, pressure sensitive keys may be configuredto use rubber dome keys with conductive half-spheres or half-domeslocated on the underside of the rubber domes. In such an embodiment, thefollowing principle may be employed: as the conductive sphere is pressedharder against a printed circuit board (PCB) or flexible PCB underneathit, the conductive sphere's surface area contact increases withpressure, thus increasing the capacitance of that contact inrelationship with a nearby charged trace. The capacitance can bemeasured and sent to a keyboard controller as alternating open/short(alternating off/on) digital signals representative of the measuredcapacitance value without the need for further analog to digital signalconversion. The embodiments disclosed herein, therefore, can useanalog-based variable-pressure keys and incorporate them withdigitally-based momentary-on switches of typical keyboards to make akeyboard that supports both regular make/break keys and keys withvariable finger pressure sensitivity, and at the same time that iscompatible with legacy “momentary-on” measurement keyboard controllerssuch as are typically found in information handling systems such asnotebook and desktop computers. This variable finger pressuresensitivity is particularly useful for gaming applications where thereis a consistent need for more intuitive gaming interfaces.

For keyboards with both types of keys, signal inputs from both types ofkeys can be provided in one embodiment to a keyboard controller via adigital input block. For example, digital input can be provided directlyto the keyboard controller by the typical keyboard array of momentary-onswitches. These are the keys that operate as either switch on or off,essentially providing a digital 1 or 0 back to the microcontroller.Capacitive-sensing or other key pressure-sensing circuitry can also bepresent for providing alternating open/short digital input signals forthe keyboard controller that are representative of the amount ofpressure applied to a given pressure sensitive key at any given time. Atthe same time, the keyboard controller can also support any number ofdigitally based momentary-on switch based keys. The capacitive-sensingor other key pressure-sensing circuitry may also provide key pressureindication signals (e.g., as a digital output signals or other suitablesignal type) to haptics control circuitry that are representative of theamount of pressure applied to a given pressure sensitive key. Thehaptics control circuitry may be configured to in turn produce a hapticscontrol signal that corresponds to the pressure level (i.e., amount offorce) applied to the given pressure sensitive key (e.g., as a vibrationwaveform having a vibration intensity corresponding to the pressurelevel). The haptics control circuitry may provide the haptics controlsignal to haptics actuation circuitry that will be described furtherherein.

In the practice of the disclosed systems and methods, pressure sensingmeasurement circuitry (e.g., such as capacitive-sensing digital outputcircuitry) and corresponding haptics control circuitry may be, forexample, embedded or integrated within a keyboard controller, though itmay also be located external to the microcontroller as well. In thelatter case, a “drop-in” keyboard having both conventional momentary-onand pressure sensitive keys, as well as haptics control circuitry andassociated haptics actuation circuitry (e.g., including piezotransducers) for one or more of the keys, may be provided that hasdigital outputs for both momentary-on and pressure sensitive types ofkeys that are compatible with a legacy digital keyboard controller. Thiscapability may be advantageously employed, for example, to enable abuild-to-order methodology in which either type of keyboard (i.e.,traditional keyboard with only momentary-on keys or gaming keyboard withat least some pressure sensitive and haptics-enabled keys) may beselectively assembled to a common information handling system notebookchassis or common desktop keyboard chassis having a legacy keyboardcontroller, e.g., based on details of a specific customer order.

In one embodiment, for example, the pressure sensitive keys may bevariable capacitance pads that are coupled to provide an analog signalinput to capacitive-sensing digital output circuitry available fromTexas Instruments of Dallas Texas and having part number MSP430F2111.However, any other type of suitable capacitive-sensing digital outputcircuitry may be employed including, for example, any circuitry thatuses RC discharge time to measure sensor capacitance as described inU.S. Pat. No. 3,936,674, which is incorporated herein by reference inits entirety. The capacitive-sensing digital output circuitry may befurther optionally provided (integrally or separately) with signalswitching circuitry, e.g., switch circuitry configured to interface withthe legacy keyboard matrix array (e.g., 16 columns×8 rows) which requirecurrent sinking capability as well as to provide for capability ofproviding pressure sensitivity to all keys in a keyboard.

Examples of suitable signal switching circuitry for interfacing with alegacy keyboard controller include, but are not limited to,optoisolators or MOSFET switches that interface with the keyboardcontroller in a manner as will be described further herein. Themomentary-on switch based keys input (when present) can be sent via, forexample, a 24-bit digital path to the digital I/O of the keyboardcontroller, e.g., legacy 8051-based microcontroller available fromsources such as Intel, Infineon Technologies, NXP, Silicon Laboratories,etc. The keyboard controller can also have an optional embedded I2Cmaster/slave block used to talk to peripheral ICs (integrated circuits)for additional functionality. A serial EEPROM can also be optionallyprovided as part of the keyboard to communicate with the keyboardcontroller, for example, to provide the VID (vendor identification) andDID (device identification) information to the microcontroller via theI2C bus.

It is further noted that for an electronic lighting control embodimentwhere aspects of key lighting are implemented for the keyboard, acombination pulse width modulator (PWM) and LED (light emitting diode)driver integrated circuit can be used, such as part number MAX6964AEGavailable from Maxim. Such integrated circuits, for example, can receivecommands from a host system, such as a personal computer, through thekeyboard controller to drive RGB (red, green, blue) LEDs for keyboardlighting as instructed by the host system. The personal computer or hostsystem, for example, can be configured to communicate with the keyboardcontroller through a USB connection, and the keyboard controller can beconfigured to convert these commands into a serial I2C stream providedto the PWM and LED driver integrated circuit which can in turn pulsewidth modulate the correct amount of light dimming and color to beprovided for the keyboard lighting.

The haptics control circuitry may be, for example, a MAX11835 Rev. 2chip (available from Maxim Integrated Products, Inc. of Sunnyvale,Calif.) that is capable of storing up to 16 different vibrationwaveforms, and which may be coupled to receive key pressure indicationsignals (e.g., as high/low digital signals) from the pressure-sensingdigital output circuitry (e.g., TI MSP430F2111 controller). The hapticscontrol circuitry may in turn provide haptics control signals (e.g., inthe form of selected vibration waveforms having a vibration intensitycorresponding to the pressed key pressure level) to haptics actuationcircuitry of the pressed key. The haptics actuation circuitry providedfor each key may be, for example, a piezo transducer such asKBS-20DA-3AN available from Kyocera Corporation of Kyoto, Japan, or maybe another type of piezo transducer (e.g., available from sources suchas CUI Inc. of Tualatin, Oreg. or Murata Manufacturing Company Ltd. ofKyoto, Japan).

As described further below, a common injection-molded silicon rubbersheet can be used with built in rubber domes and a common flex circuitryto support both digital momentary-on switches and pressure sensitivesensors (e.g., variable resistance or variable capacitance). Forvariable capacitance sensing, as the user's finger applies pressure tothe plastic keycap, it can be configured to press on the depressiblerubber dome which has a conductive spherical shaped actuator on thebottom side. As the keycap is pressed, the conductive spherical shapedactuator comes into contact with one plate of a capacitor. An insulatinglayer is located above a second plate for the capacitor so that it isisolated from the first plate. Thus, the conductive actuator does notcontact the second plate, and a capacitance develops between the twoplates. As the user puts more pressure onto the keycap, more surfacearea of the conductive material from the conductive actuator will lieover first plate thereby increasing the capacitance between the twoplates.

Haptics actuation circuitry may be provided for one or more keys of avariable pressure sensitive keyboard using any suitable methodology. Forexample, a piezo transducer may be mounted to the bottom keyboardhousing in position beneath the bottom second capacitor plate of avariable capacitive sensing keyboard such as of the type describedabove. Alternatively, a piezo transducer may be molded into a keycap ormounted on the underside of the keycap, e.g., in a manner that does notinterfere with transmittal of light for backlighting the individualkeys.

In operation of one embodiment of the keyboard, the amount of fingerpressure applied by a user to a given key is sensed by the pressuresensing (e.g., variable capacitance sensing) digital output circuitryand is digitally provided to the keyboard controller via switchingcircuitry (e.g., optoisolator, MOSFET, etc.) that provides alternatingopen/short signal current pull down signals to the keyboard controllerin a manner that emulates toggling of a conventional momentary off/ondigital key. The pressure sensing digital output circuitry may alsosimultaneously provide a digital signal (e.g., high/low digital signal)representative of user-applied finger pressure to the haptics controlcircuitry, which in turn provides a haptics control signal representinga haptics motion (e.g., vibration) intensity corresponding to the amountof user pressure applied to the pressed key.

In an optional embodiment, configuration information provided by a usermay be employed to adjust the operation of the pressure sensitive keys,e.g., via the pressure-sensing circuitry, other processing device, orsoftware executing on a host system to which the keyboard is coupled.This user configuration information, for example, can optionally adjustthe sensitivity and output levels generated by the Pressure SensingInterface Circuitry based upon the pressure sensitive signals receivedwith respect to the pressure sensitive keys as described in U.S. patentapplication Ser. No. 12/316,703 filed Dec. 16, 2008, which isincorporated herein by reference in its entirety. The keyboardcontroller can then in turn provide output signals to the host systemthat indicate pressure amounts. The host computer can then use thesekeyboard output signals with respect to particular software applicationfunctions being operated by the host computer. For gaming applications,such pressure sensitive functions may include the variability in thespeed of travel (slow walk, trot, run, etc.), the amount of turning(slow, fast, etc.), the amount of strafing for a first-person-shootgame, the amount of braking for a vehicle race game, the degree of therate of fire, the height of one's jump, and/or any other desiredvariable gaming feature.

FIG. 1 is a block diagram for a keyboard system 100 including pressuresensitive and haptics-enabled analog keys 104 together with digital keys106. However, it will be understood that in other embodiments, akeyboard system may be provided only with haptics-enabled analog keys,with both haptics-enabled analog keys and haptics-enabled digital keys,or only with haptics-enabled digital keys. As depicted, for thisembodiment a keyboard controller 110 is coupled through pressure sensinginterface circuitry 185 to analog keys 104 of a key area 102 that ispart of a keyboard device body. In this embodiment, the key area 102includes both analog keys 104 and digital keys 106 (e.g., in oneembodiment key area 102 may include a QWERTY keyboard), although anyother style of multi-key key area may be employed. The digital keys 106represent keys that are momentary on keys that are detected as eitherdepressed or not depressed. When a digital key is depressed, an outputsignal is sent to an I/O interface in the form of digital input block112 within the keyboard controller 110. The analog keys 104 representkeys that are detected as being depressed by a variable amount or with avariable amount of pressure and that are each enabled to produce hapticsmotion feedback to a user indicative of the amount of pressure currentlybeing applied to the pressed key by the user. In one embodiment, all ora portion of keys 104 and 106 may each be implemented using separatelyactuatable independent mechanical key structure mechanisms withcorresponding separate key output circuitry and/or haptics actuationcircuitry, and not implemented using membrane key output and/or membranehaptics elements of a multi-key-membrane style keyboard, although inother embodiments multi-membrane-style keys may alternatively byemployed.

When an analog key 104 is depressed, an indication of the force orextent to which it is depressed is provided to pressure sensinginterface circuitry 185 that in the illustrated embodiment includespressure-sensing digital output circuitry 190 and switching circuitry192. Pressure sensing interface circuitry 185 in turn provides a keypressure indication signal 145 that indicates the force or extent towhich the key 104 is depressed to haptics control circuitry 160 which iscoupled to actuate haptics motion to the pressed analog key by a hapticscontrol signal 147. Also illustrated in FIG. 1 is optional hapticscontroller 162 that may be present in haptics control circuitry 160 insome embodiments, and which is further described herein. Pressuresensing interface circuitry 185 and/or haptics control circuitry 160 mayeach be provided in one exemplary embodiment as part of the keyboarddevice body. However, digital input block 112 and one or more componentsof pressure sensing interface circuitry 185 and/or haptics controlcircuitry 160 may alternatively be integrated within a microcontrollerthat is operating as the keyboard controller 110 and/or as part of thehost system to which the keyboard is connected, if desired. The digitalinput block 112 and one or more of the components of pressure sensinginterface circuitry 185 and/or haptics control circuitry 160 could alsobe implemented with external circuitry, as well.

Still referring to FIG. 1, the pressure-sensing digital output circuitry190 includes a pressure sensing block 198 that receives an analog signalrepresentative of the pressure applied to each of analog keys 104 andthen outputs an alternating key pressure indication signal in the formof a high and low (high/low) digital output bit stream signal 133 havinga frequency that is representative of this pressure being applied toeach of analog keys 104 to a corresponding switching element ofswitching circuitry 192 (e.g., optoisolator, transistor such as MOSFETs,etc.). Each switching element of switching circuitry 192 responds to adigital signal 133 corresponding to a given analog key 104 by providinga toggled key pressure indication signal in the form of alternatingopen/short (off/on) digital signal 135 to a corresponding intersectionpoint in the 16×8 key matrix which corresponds to that analog key 104 ina manner as described further herein. Pressure sensing block 198 alsooutputs an alternating high and low (high/low) digital output bit streamsignal 145 as a key pressure indication signal carrying a bit streamthat is representative of this pressure being applied to the analog key104 to haptics control circuitry 160. It will be understood that anytype of signal (e.g., signals 133, 135 and 145) that is representativeof pressure applied to a given key may be characterized as a keypressure indication signal.

It will be understood that the particular embodiments illustrated hereinare exemplary only, and that the components and function of pressuresensing interface circuitry 185 may be implemented using any one or morecircuitry components suitable for receiving analog signalsrepresentative of key pressure from pressure sensitive keys 104 andproviding corresponding alternating open/short digital output signalshaving a toggled frequency that is representative of key pressure frompressure sensitive keys 104 that is suitable, for example, for digitalinput to a legacy keyboard controller 110, and for also providing asignal representative of key pressure from pressure sensitive keys 104to haptics control circuitry 160. Further, the components and functionof haptics control circuitry 160 may be implemented using any one ormore circuitry components suitable for receiving signals 145representative of key pressure from pressure sensing interface circuitry185 and for providing a haptics control signal 147 to cause hapticsactuation circuitry of analog keys 104 to produce a variable hapticsmotion characteristic corresponding to the pressure level applied to thegiven pressure sensitive key (e.g., as a vibration waveform having aparticular vibration intensity and/or frequency that corresponds to thecurrently applied real time key pressure level). It will also beunderstood that one or more pressure sensitive keys may behaptics-enabled using haptics actuation circuitry that is configured toimpart haptics motion to the respective one or more pressure sensitivekeys based on key pressure indication signals received from any suitablecircuitry configuration, e.g., received from either haptics controlcircuitry 160, or alternatively received directly from pressure-sensingdigital output circuitry 190 (e.g., as signals 133, 145 and/or 135)without requiring the presence of haptics control circuitry 160.

The control circuitry 120 within the keyboard controller 110 is coupledto receive on/off signals from the digital input block 112. The controlcircuitry 120 processes this key information and is connected to anoutput communication interface 118 so that this key information can becommunicated to external devices, such as host components of aninformation handling system, through communication path 122. Inaddition, external devices can optionally communicate control and/orother configuration information to the keyboard controller through thissame output communication interface 118 through communication path 122.Examples of possible information handling system components may be founddescribed in U.S. patent application Ser. No. 12/586,676, filed Sep. 25,2009, which is incorporated herein by reference in its entirety.

It is noted that the output communication interface 118 andcommunication path 122 can take a variety of forms. The communicationpath 122 can be a wired communication path or a wireless communicationpath, as desired. With respect to personal computer systems, such asdesktop computers and laptop computers, the output communicationinterface 118 will often be a Bluetooth interface if a wirelessinterface is desired and will often be a USB (universal serial bus)interface if a wired interface is desired. However, it is again notedthat any desired communication interface can be utilized. It is furthernoted that the keyboard controller 110 and the control circuitry 120 canbe implemented as a microcontroller (e.g., legacy 8051-basedmicrocontroller or custom microcontroller) that runs firmware stored ona memory device associated with the keyboard controller 110 and/orcontrol circuitry 120.

It is also noted that the user configuration information 196 can beoptionally stored in random access memory (RAM) or other memory storagethat is associated with pressure sensing circuitry 190 (eitherinternally or externally). Thus, the configurable analog key controlparameters 196 can be stored, for example, on a RAM device in thekeyboard or on the host system (e.g., on a hard drive) and can provide awide variety of configurable parameters that can be adjusted by a userthrough an application programming interface (API) to a software utilityapplication that, for example, has a graphic user interface (GUI) toallow a user to edit the parameters through the software utility. Forexample, the user configuration information may be stored, for example,in nonvolatile or volatile memory on board the keyboard system 100.Alternatively, the user configuration information may be stored on thehost system or other device that is coupled by communication path 122 tooutput interface 118 off keyboard controller. Either way, single and/ormultiple different user configuration files and/or multiple game (orapplication) configuration files may be stored allowing a user to selectthe applicable or desired keyboard configuration file depending on thegame or application being used by the user and/or depending upon theparticular user using the keyboard at the time in a manner as describedin U.S. patent application Ser. No. 12/316,703 filed Dec. 16, 2008,which is incorporated herein by reference in its entirety.

FIG. 2A is a diagram for an exemplary embodiment 200 for a flexible-domestyled keyboard such as may be employed in USB full size keyboards. Inillustrated embodiment of FIG. 2A, the key structures include ahaptics-enabled analog key and a digital key. In operation, depressingthe analog keycap 202 causes key output circuitry of a key structurethat includes keycap 202 to produce a variable or analog output 220 tobe provided by the keyboard, and depressing digital keycap 203 causes adigital or on/off output 222 to be provided by the keyboard. The analogkeys provide a variable output, and the digital keys provide amomentary-on output. As depicted, the embodiment 200 has a layeredstructural approach that overlays a base 212. One or more of pressuresensitive analog keys 104 may be implemented in this embodiment by a keystructure that includes a separate (e.g., hard plastic) keycap 202, aseparate conductive and resilient and flexible half-dome structure 216,and separate haptics actuation circuitry in the form of a piezotransducer 260 that is provided as separate (i.e., non-membrane style)circuitry from the haptics actuation circuitry of any other keystructure of the keyboard. In one exemplary embodiment (e.g., as may beimplemented with a variable capacitive methodology), flexible half-domestructure 216 may be a GRSP pill as manufactured by ARC USA, Inc. Such aGRSP material is a non-silkscreen conductive ink which is manufacturedin a half-dome “pill” form with a soft (rubberish-like) material andthat may exhibit a good operation life (number of switching actuations).In another exemplary embodiment (e.g., as may be implemented with avariable impedance methodology), flexible half-dome structure 216 may bea conductive pill made by ShinEtsu Polymer America, as used in theirTouchDisc products. In one exemplary embodiment, a pill may be co-moldedonto the same silicon rubber sheet with which rubber domes (213 and/or215) are made from.

As shown in FIG. 2A, base 212 may be configured in this embodiment tocontain the corresponding separate haptics actuation circuitry 260 ofeach separate key structure in a manner described further below. In sucha configuration, each haptics-enabled key structure may be characterizedas a separately acutatable independent mechanical key structuremechanism with corresponding separate key output circuitry and/orhaptics actuation circuitry, i.e., that is not implemented usingmembrane key output elements of a multi-key-membrane style keyboard.However it will be understood that it is possible that in otherembodiments multi-membrane-style keys may alternatively by employed.

In the layered structure of FIG. 2A, base 212 represents the bottom ofthe layered structure and can be made of a material that can support thekey structure, such as a hard plastic material that may also serve asthe bottom keyboard housing material. A flexible PCB (printed circuitboard) 210 is then provided on top of the base 212. The PCB 210 includescircuit traces or connections that provide for electrical signals to begenerated and communicated when keys are depressed. For example, circuitconnection 236 is used to provide digital output 222, and circuitconnection pads 230 and 231 are used to provide the analog output 220.The next layer is flexible insulator 208, such as a flexible PCB withoutcircuit connections. The next layer is another flexible PCB 206 that caninclude circuit traces or connections that work in conjunction with theconnections on PCB 210 to provide for electrical signals to be generatedand communicated when keys are depressed. For example, circuitconnection 234 is used to provide the digital output 222. A relativelythin flexible layer 204 can then be provided above PCB 206 and can bemade from an injection molded silicon rubber sheet. This flexible layer204 is configured to have a molded flexible rubber dome for each key.For example, flexible dome 215 is provided for analog keycap 202, andflexible dome 213 is provided for digital keycap 203. In one exemplaryembodiment, flexible dome 216 may be co-molded to the rubber dome sheet204.

Still referring to the exemplary embodiment of FIG. 2A, hapticsactuation circuitry 260 in the form of a piezo transducer may be mountedto (and optionally within) base 212 (e.g., which may be a bottom plastickeyboard housing material structure). In this embodiment, piezotransducer 260 includes a metal plate 273 (for signal +) and ceramiccapped electrode 275 (for ground). An example of such a piezo transduceris KBS-20DA-3AN, available from Kyocera Corporation. As shown in FIG.2A, piezo transducer 260 may be mounted underneath the bottom-most layer210 of flex circuitry, yet on the upper or top-side surface of base 212of the keyboard. In this embodiment, piezo transducer 260 is mounted ona raised piezo support structure 266 that is protrudes upward within acavity 264 of the base 212, e.g., such that the raised support structure266 is surrounded by a depression or “valley” area. In this embodiment,raised piezo support structure 266 is provided as a circular rib havinga diameter that is less than the outer diameter of the metal plate 273of piezo transducer 260 in a manner such that the outer diameter of thecircular rib does not exceed the diameter of the inner circle (ceramiccapped electrode 275) of piezo transducer 260. This allows the outerdiameter structure of the piezo transducer 260 (e.g., metal plate 273with a varying electrical input pulse applied to it) to flex (e.g.,contract/expand) or flap up and down without restriction in order toproduce a vibration haptics motion for the key. In this embodiment, thehaptics vibration is up and down, e.g., in a direction parallel to theup and down key travel direction of key cap 202 that is illustrated inFIG. 2D.

A raised piezo support structure 266 may alternatively be provided inthe form of a boss or combination of a boss and a rib. Further, as shownin FIG. 2B, optional support ribs 268 may be provided to ensure adequatesupport for the piezo transducer 260, and to ensure that when the key ispressed that the flexible half-dome structure 216 presses against a flatbottom with adequate pressure distribution due to the ribs. This in turnmay increase the reliability of piezo transducer 260 by making it lessprone to mechanical damage due to inadequate mechanical support fromunderneath. Optional support ribs 268 may be shaped in such a way so asto provide mechanical support under ceramic capped electrode 275 so thatceramic capped electrode 275 substantially does not mechanically flexwhen pressed upon by flexible half-dome structure 216. In oneembodiment, the diameter of raised piezo support structure 266 may beequal or greater than the diameter of flexible half-dome structure 216when pressed with maximal force so as to ensure substantially nophysical damage to piezo transducer 260 when pressed on by flexiblehalf-dome structure 216 with a lot of force. In any case, the raisedpiezo support structure 266 is shaped and dimensioned to providesufficient mechanical support to the piezo transducer 260 to ensure noflexion when pressed upon by the overlying key structure, while at thesame time providing a solid bottom or base for the rubber dome key topress against to “make” the electrical connection (i.e., to indicate akey press).

Piezo transducer 260 may be mounted to raised piezo support structure266 using any suitable methodology e.g., adhesives such as epoxy orsilicon, mechanical mounting such as by press molding, etc. In oneembodiment, piezo transducer 260 may be mounted to raised piezo supportstructure 266 using a dampening mounting structure 262 (e.g., such as1/32 inch thick 3M Double Coated Polyethylene Foam Tape model 4492W,having a conformable closed cell foam with a high strength acrylicadhesive that provides high adhesion strength to a wide variety ofsurface materials. In one particular exemplary embodiment, a dampeningmounting structure 262 may be a 35-55 mil thick×½ inch diameterdouble-sided adhesive rubberized “Glue Dot”, such as GlueDot model no.XD32-402, available from Glue Dots International, an Ellsworth AdhesivesCompany, Germantown, Wis. Such a Glue Dot may be manufactured to have ahigh tack strength adhesive for industrial applications. It will beunderstood that such Glue Dot double-sided adhesive products may beselected to have varying tack (strength) levels, varying thicknessesfrom 12 mils to 100 mils, and/or custom made to meet specific mechanicalneeds of a given application. When employed, a rubberized or dampeningconsistency of a mounting structure may be selected in order to dampentransmittal of the vibration of the piezo transducer 260 through thepiezo support structure 266 to the base 212, while at the same timeallowing transmittal of the piezo transducer vibration through layers210/208/206, flexible half-dome structure 216 and flexible dome 215 tothe keycap 202 and the user's finger when the keycap 202 is pressed downby the user in the manner shown in FIG. 2D to cause downward key travelof key cap 202 relative to base 212. It will be understood that thethicknesses of dampening mounting structure 262 may be varied to finetune the degree of dampening required to obtain the desired degree ofvibration in the key cap (202 and/or 203) while dampening any vibrationfrom entering back into the keyboard housing via base 212.

As shown in FIGS. 2A and 2B, the height of the circular rib 266 is lessthan the height of the top surface 269 of base 212 by a distance “x”that is equivalent to the combined thickness of piezo transducer 260 anddampening mounting structure 262 such that the top surface 271 of piezotransducer 260 is coplanar (disposed in the same plane) or parallel totop surface 269 of base 212 when piezo transducer 260 and dampeningmounting structure 262 are assembled to piezo support structure 266 asshown by dashed lines 281 in FIG. 2C. Such a configuration may beemployed to ensure that all keycaps 202 press downward against a surfacewhich is disposed along a common plane for each keycap 202. As shown,flex layer 210 may be utilized to route piezo signals (+ and −) via flextrace 279 to haptics actuation circuitry 260.

For the digital key of FIG. 2A, an actuator 214 is also providedunderneath the dome 213 that causes circuit trace 234 to be engaged withcircuit trace 236 when the digital keycap 203 is depressed. When circuittrace 234 touches the circuit trace 236, a signal is now activeindicating the key was pressed, causing a digital output 222 to begenerated. This digital output 222 can be configured to provide amomentary-on indication of whether or not the key has been depressed.The digital keycap 203 can be made from hard plastic.

For the analog key, the conductive and flexible half-dome 216 isprovided to flex when depressed, as described in more detail below, tovary the capacitance associated between circuit pad 231 and circuit pad230 when analog keycap 202 is depressed. At the same time flexiblehalf-dome flexes to contact circuit pad 231 through which hapticsvibration motion is transmitted from piezo transducer 260 when keycap202 is depressed. FIG. 2D shows assembled keyboard embodiment 200 withkeycap 202 so depressed. Notice that as pressure is applied to the key,flexible half-dome structure 216 not only comes into contact withcircuit pad 231, but its surface area on insulator layer 208 starts toincrease due to the pressure. With a maximum pressure, the half-dome 216contact diameter of half-dome 216 on surface of insulator layer 208approaches that of the diameter of pad 230. As the contact surface areaof the half-dome 216 on surface of insulator layer 208 increases, sodoes the capacitance as measured at signal 232. Flexible half-dome 216may be resilient so as to return the depressed keycap 202 to itsunpressed condition when the keycap 202 is no longer depressed.

Essentially pad 231 and pad 230 are the two plates of a capacitor. Thevariable capacitance between these two plates are measured from signaltrace 232 by sending this trace to capacitance reading circuitry. Asstated below, pad 230 can be coupled to ground. It is noted that theconductive and flexible half-dome 216 can be made, for example, from aconductive rubber material, that is conductive, flexible and capable ofreforming its shape after being depressed and released. Examples ofsuitable materials are discussed above. Further, prior art techniqueshave made this material from a carbon impregnated rubber.

It will be understood that one or more keys of a keyboard assembly maybe provided with haptics circuitry in a variety of alternative ways withkey output circuitry implemented between a keycap 202 and underlyinghaptics actuation circuitry 260 that is mounted to (and optionallywithin) base 212 in a manner described elsewhere herein. Furthermore,different types of keyboard assemblies may be provide with hapticscapability, including both desktop information handling system keyboardsand keyboards for portable information handling systems, such asnotebook computers. For portable information handling system keyboardassemblies, the mounting of a piezo transducer or other hapticsactuation circuitry to the keyboard base (under the flex layers or otherkey output circuitry) as described in relation to FIGS. 2A-2D may not bea desirable option, due to a different key structure that is oftenemployed to maintain a low Z height profile for portable informationhandling system keyboards. Further, for any type of under key lightedinformation handling system keyboard, the haptics circuitry needs to bemounted in such a way that intervening opaque materials (e.g., layers)don't obstruct the light produced under the key used for backlightingthe key.

FIG. 2E illustrates an example of an alternative embodiment in whichhaptics actuation circuitry may be implemented between the key outputcircuitry and the keycap 702. In this exemplary embodiment, FIG. 2Eillustrates the mounting of piezo transducer type haptics circuitry tothe underside of a backlighted keycap 702 of a keyboard such as employedfor an Alienware model m11x, m15x and m17x notebook computers availablefrom Dell Computer of Round Rock, Tex., although other types of keycapsmay be employed. Such a low profile keyboard may employ a collapsibledual lever action key mechanism that supports the keycap 702 byutilizing mating lever members 722 and 724 that are secured at one endthrough intervening layers 210, 208, 206 and 704 to a metal base 712 ofan analog pressure sensitive keyboard assembly 700 at a hinge point 710and to a slideable stopper 711 at the other end. The mating levermembers 722 and 724 are configured to pivot downward relative to eachother with a scissor-like action when the keycap 702 is depressed, andare provided with a resilient member that returns the keycap 702 upwardto its unpressed position when the keycap 702 is no longer pressed. Anexample of such a collapsible key mechanism may be found in Flextronicsmodel no. DELH-B2625040G00001 keyboard (e.g. as found in the Alienwarem15x) and manufactured by Darfon of Gueishan, Taoyuan 333, Taiwan,R.O.C.

As shown in FIG. 2E, a single layer disc type piezo transducer 260 ismounted on the underside of keycap 702 such that the larger diametermetal plate 273 of the transducer is mounted against the keycap within acomplementarily-dimensioned recessed area 703 (e.g., adhered to and/ormechanically mounted by sliding into grooves 950 provided in the sidesof recess 703 as shown by the arrows in FIGS. 2H and 2I), and with thesmaller diameter ceramic electrode portion 275 of the transducer facingdownward toward a transparent or translucent flexible rubber domestructure 705 which extends through an opening 707 provided in a topflex circuit layer 704. A conductive and flexible half-dome structure216 is provided to flex when depressed as previously described to varythe capacitance associated between circuit pad 231 and circuit pad 230when analog keycap 702 is depressed.

Still referring to FIG. 2E, a two-wire flex circuit 279 may be providedas shown to electrically connect the piezo transducer 260 (e.g., KyoceraCorporation, Model No. KBS-20DA-3AN piezo transducer) to the top flexcircuit layer 704. Top flex circuit layer 704 is typically printed withblack ink and used in non-haptics enabled keyboard assemblies only forpurposes of blocking light from an underneath backlight element 750(e.g., RGB LED, single color LED, etc.) from bleeding through atlocations between openings between backlit keys. In this embodiment, thebacklight element 750 shines thru the side of a polycarbonate sheet 751which acts as a backlight-light spreader, to spread the backlight undermany keys. However, in the illustrated embodiment of FIG. 2E, thisexisting layer 704 of flex circuit may be used to route signals betweenthe haptics circuitry (e.g., piezo transducer 260) and haptics controlcircuitry which is described further herein.

As previously described and illustrated in FIG. 2E, piezo transducer 260or other type of haptics circuitry may be mounted into a recessed area703 that is molded into the bottom side of a keycap 702. This particularconfiguration allows for easier assembly in manufacturing, providesprotection to the piezo transducer from flexion, and helps improve thereliability of the rubber dome 705 by preventing it from gettingaccidentally punctured from any sharp edges on the piezo (e.g., such asby solder connection to the wires 279 or flex circuitry 704). However,haptics circuitry may be mounted to the bottom side of a keycap 702using any other suitable methodology, e.g., using double sided adhesivefoam tape or an adhesive “Glue Dot” such as described in relation toFIGS. 2A-2D. Further, flex cable 279 may be routed from the side of thekey where the dual-lever scissor action key switch pivots fromconnection between levers 722 and 724 to help avoid flex cable 279 fromgetting accidentally pinched by the action of dual levers 722 and 724when keycap 702 is pressed by a user. In one embodiment, an openingcomplementary to the outer dimensions of rubber dome 705 may be formedin both levers 722 and 724 through which rubber dome 705 upwardlyextends such that the top surface of the rubber dome 705 rests upon thebottom surface of ceramic electrode 275 of piezo transducer 260. When abacklit keyboard is desired and an opaque piezo transducer 260 isemployed, a light pipe may be optionally added to keycap 702 to transferbacklight light as it shines through flex circuitry 704 where there's noblank ink acting as an aperture control.

FIGS. 2F and 2G illustrate alterative embodiments of multi-parthaptics-enabled keycap assemblies that may be employed for “chimneystack” style key applications such as used for USB or desktop computertype keyboards. Such keyboards may employ chimney stacks that may beprovided, for example, as circular or square cross-sectional plasticrods connected to the keycap that press down onto a rubber dome to whichprovide a spring-like action to return the key back up to position whenno finger is pressed on it. Disclosed herein are two-piece keycaps thatmay be provided in one embodiment in the form of a keycap that's moldedor adhered onto a chimney stack once the piezo is mounted inside of itsuch that the piezo is very close to the finger (under key cap) tostrengthen the vibration haptics effect felt by the user while at thesame time weakening the haptics vibrations transferred to the keyboardhousing or base 212.

In the exemplary embodiment of FIG. 2F, a piezo transducer 260 or otherhaptics circuitry may be molded as part of a multi-piece keycapstructure that is assembled together at the factory. As shown, piezotransducer 260 is mounted within a recessed area 803 of keycap 802 thatis then molded to chimney stack 804 which is in turn received within acomplementary aperture of key guide 806. Piezo transducer 260 is thusconfigured in a position in which it is allowed to flex (or vibrate)underneath the keycap lid 802 once keycap 802 is applied and sealed tothe chimney stack 804 with piezo transducer 260 positioned therebetween.As shown, flex circuit 279 connects piezo transducer 260 to underlyingpiezo control circuitry through access opening 811 that is defined in asurface of the keyboard assembly through which key guide 806 withchimney stack 804 key guide downwardly extends to key activationcircuitry that senses when each keycap 802 is depressed downward withits respective chimney stack 804. In this regard, each chimney stack 804“spring loaded”, via a rubber dome located inside circular opening 806whereby cylindrical shaped chimney stack 804 presses against the topsurface of the rubber dome, to return to a raised position when downwarduser key pressure is removed.

In the exemplary embodiment of FIG. 2G, a piezo transducer 260 may bemounted within a recessed area 903 of a chimney stack 904 that is thenmolded to keycap 902 with piezo transducer 260 positioned therebetween.Chimney stack 904 is in turn received as shown within a complementaryaperture of key guide 906. Piezo transducer 260 is thus configured in aposition in which it is allowed to flex (or vibrate) underneath thekeycap lid 902 once keycap 902 is applied and sealed to the chimneystack 904 with piezo transducer 260 positioned therebetween. As with theembodiment of FIG. 2F, flex circuit 279 connects piezo transducer 260 tounderlying piezo control circuitry through access opening 811 that isdefined in a surface of the keyboard assembly through which key guide906 with chimney stack 904 key guide downwardly extends to keyactivation circuitry that senses when each keycap 902 is depresseddownward with its respective chimney stack 904. In this regard, eachchimney stack 904 is “spring loaded”, via a rubber dome located insidesquare shaped opening 906 whereby rectangular shaped chimney stack 904presses against the top surface of the rubber dome, to return to araised position when downward user key pressure is removed.

Referring to the exemplary key output circuitry embodiment of FIG. 3B,to measure the capacitance change, plate two 230 may be connected toground, and plate one 231 may have a trace connected to it that isrouted to an I/O pin on pressure-sensing digital output circuitry 190(e.g., TI MSP430 controller). The conductive material for the capacitiveactuator may either be impregnated into the rubber dome material, or maybe an external piece of material that is attached to the rubber dome viaco-molding, mechanical/snap-in means, via adhesive, or a hot fusingmethod. Other methods for providing a conductive and flexible actuatorcan also be used.

As shown in more detail with respect to FIG. 3B described below,electrical pad 230 is shaped like a donut with an insulative material inthe middle. Circuit trace 232 connects to the circuit pad 231 through avia within the insulative material with the conductive pad 231 beinglocated in the middle of the insulative center of the donut area. Pad230 may be attached to a signal trace, but the preferred method ofembodiment has pad 230 being coupled to a given charge, such as beingattached to ground. Due to insulator layer 208, the conductive half-dome216 may only make contact to circuit pad 231 through the hole in theinsulator 208.

As described further below, as the conductive and flexible half-dome 216makes contact with circuit pad 231 and is deformed by pressure from theanalog keycap 202, the capacitance between pad 231 and pad 230increases. As more pressure is applied to the analog keycap 202, thehalf-dome 216 gradually deforms and flattens-out on top of theinsulator, causing a larger conductive surface area to run parallel topad 230. Effectively, there are two parallel plates provided by pads 231and 230 with a fixed thickness insulator/dielectric between them. Pad230 has a fixed surface area as it is printed onto the PCB 210. However,pad 231 has a variable surface area or is a variable sized parallelplate due to the action of half-dome 216 as it is depressed. As thesurface area of pad 231 gradually increases due to action of half-dome216 as greater force is applied to the analog keycap 202, thecapacitance between plates 231 and 230 gradually increases as well. Thisvariable capacitance can be sensed, measured and used as an indicationof the pressure being applied to the analog keycap 202. When implementedusing variable capacitance methodology, the sensor may be implemented onthe PCB directly. However, it will be understood that haptics enabledkeys may be implemented with other types of pressure sensitive keys(e.g., via the use of force sensitive resistors or the conductiveflexible half-dome material —both of which employ materials that changetheir electrical impedance with applied pressure) using hapticscircuitry and/or haptics control circuitry described herein. Further, itwill be understood that conventional digital keys may be provided withhaptics capability using systems, apparatus and/or methods describedherein.

In one embodiment disclosed herein, pressure sensitive capacitive keysmay be configured to generate a variable indication of how hard a keyhas been depressed. In this regard, FIG. 3A is a diagram for differentdepressed states for the conductive and flexible half-dome structure 216of FIG. 2A. In its initial state, the bottom edge of the half-domestructure 216 has a bottom edge position indicated by Line 1. As the keyis depressed, the half-dome structure 216 will move through the gap inthe Flex PCB layer 206 (see FIG. 2A) and down towards insulator 208 andconnection pad 231 on PCB 210. Line 2 represents the bottom edge ofhalf-dome structure 216 when it has been depressed some distance. Line 3represents the bottom edge of half-dome structure 216 when it has beendepressed far enough to touch connection pad 231 through the gap ininsulator 208. It is also noted that bottom edge will have flattened outslightly due to this contact, as shown with respect to Line 3. Line 4shows that the bottom edge of half-dome structure 216 will continue toflatten as it is depressed. And Line 5 is a further indication of thisflattening of the half-dome structure 216. As stated above, as thehalf-dome structure 216 is moved closer to connection pad 231, half-domestructure 216 will touch connection pad 231 and will then flatten outcausing a larger surface area for electrical plate 231 relative toelectrical plate 230. As the surface area of the plate 231 increases dueto increased pressure on analog keycap 202, the capacitance between pad231 and pad 230 correspondingly increases. This change in capacitance(ΔC) can be used as an indicator of the pressure that has been used todepress the key associated with the half-dome structure 216. Connectionpad 231 can be coupled to pressure sensing block 198 (ofpressure-sensing digital output circuitry 190) that operates to senseand measure the electrical information provided from connection pad 231.

FIG. 3B is a diagram for a top view of the capacitive contact pads 230and 231 for the half-dome structure. As depicted, an insulative material308 sits between the contact pad 230 and the contact pad 231. Asindicated above, the contact pad 230 can be coupled to ground. And thevariable capacitance (Cx) between the pads 230 and 231 caused by themotion of the half-dome structure 216 can be used to provide the analogoutput 220. The variable capacitance (Cx) between pads 230 and 231 canbe represented by a fixed capacitance component associated with theposition of the pads 230 and 231 (C_(fixed)) and a varying capacitancecomponent (C_(variable)) associated with the action of the half-dome216, such that Cx=C_(fixed)+C_(variable). The deforming of theconductive flexible half-dome structure 216 effectively increases thecapacitor plate area associated with the pad 230, thereby effectivelyincreasing the capacitance between pads 230 and 231. As stated above,the change in capacitance (ΔC) caused by varying capacitance component(C_(variable)) due to the half-dome 216 can be then used as an indicatorof the pressure that has been used to depress the key associated withthe half-dome structure 216.

FIG. 4A illustrates one exemplary embodiment of a keyboard system 100 inwhich analog keys 104 are haptics-enabled pressure sensitive capacitivekeys (such as described in relation to FIGS. 2A-2I, 3A and 3B), havingcapacitive pads 231 a-231 g that are coupled to pressure-sensing digitaloutput circuitry 190. One exemplary embodiment may implements thepressure-sensing digital output circuitry 190 as a Texas Instruments16-bit ultra-low power capacitive sensing microcontroller part numberMSP430F2111, however other microcontrollers may be used. In thisexemplary embodiment, pressure-sensing digital output circuitry 190 isspecifically coupled for sensing and measuring capacitance for each keyvia a corresponding general purpose input output (GPIO) port P1.0 toP1.6 that incorporates a falling edge triggered digital interrupt.Although configured in this embodiment with one GPIO input provided percorresponding single capacitive pad 231, it is alternatively possiblethat multiple capacitive pads 231 may be coupled to a single GPIO inputpin. However, for some embodiments, it may be found that less noise andimproved performance may be achieved by coupling just one capacitive padto each GPIO of pressure-sensing digital output circuitry 190.

In this exemplary embodiment, pressure-sensing digital output circuitry190 employs RC capacitive measurement methodology with falling edgeevent driven interrupt performed on a per pin basis. Information on RCcapacitive measurement may be found, for example, in U.S. Pat. No.3,936,674, which is incorporated herein by reference in its entirety.Using this methodology, each capacitive pad 231 a through 231 g ischarged and discharged via traces 131 one at a time, and the amount oftime for the discharge of each corresponding pad 231 is measured using atimer operating at a high speed (e.g., timer operating at about 16 MHzor other suitable speed). Using this methodology, the higher thecapacitance the longer the discharge time, thus providing a higherdigital “count” output from the timer of digital output circuitry 190.In this regard, as the depressible half-sphere on the bottom side of thekeycap of each capacitive pad 231 is depressed by applied fingerpressure, the amount of surface area in contact increases, thusresulting in an increased capacitance on the pad. According to thecapacitance relationship, as a plate surface area increases, itscapacitance increases.

In one exemplary embodiment, pressure-sensing digital output circuitry190 may be implemented by a TI MSP430F2111 microcontroller or othersuitable circuitry that employs RC discharge time to measure thevariable capacitance of each analog key 104 as follows. In thisexemplary embodiment, each signal lines 131 acts as a singleinput/output (I/O) line between a given falling-edge triggered interruptdigital port P1.X of pressure-sensing digital output circuitry 190 and acorresponding given analog key 104. The capacitive plate of each analogkey 104 is also coupled to ground through a resistor 199 (e.g., 6 MΩ orother resistor value selected to provide sufficiently slow RC dischargetime to provide the desired measurement resolution for the givenapplication). In this configuration, each signal line 131 is employed tocharge, discharge and produce an interrupt when the voltage of thecapacitor of analog key 104 crosses a low voltage threshold. Forexample, a given port P1.X of a given I/O line 131 may be set to outputhigh to charge (e.g., with 500 nA charging current) the capacitive plateof a corresponding analog key 104 to near V_(CC), and a free-runningtimer of the pressure-sensing digital output circuitry 190 read to markthe start time. Then the given port P1.X is set to input withnegative-edge interrupt enabled and the resistor coupled to thecapacitive plate of the corresponding analog key 104 discharges thecapacitive plate of the analog key 104 to ground, during whichpressure-sensing digital output circuitry 190 may go into low power modeto save power. When the voltage of the capacitive plate crosses aninterrupt voltage V_(IL) due to this discharge to ground, an interruptis generated which causes the free-running timer to be read again andthe elapsed time for discharge of the capacitive plate of the analog key104 from near V_(CC) to V_(IL) is calculated. Pressure-sensing digitaloutput circuitry 190 may then return to high power mode. The dischargetimer count of the capacitive plate of each analog key 104 isproportional to its present capacitance, which depends on the amount ofpressure currently applied to the key 104. In one exemplaryimplementation, multiple capacitor readings of a given analog key 104may be averaged to filter out common mode noise, e.g., by using a chargecycle followed immediately by a discharge cycle and averaging the twovalues.

Still referring to the exemplary embodiment of FIG. 4A, pressure-sensingdigital output circuitry 190 provides a corresponding digital output 133for each capacitive pad 231 and its input 131. Each digital outputsignal (P2.x) 133 corresponds to a respective capacitive pad input(P1.x) 131. In this embodiment, each digital output signal 133 isproduced in an intermittent alternating high/low manner with a frequencythat emulates the action of a user's finger toggling away at aconventional digital “momentary on” digital key at a variable speed thatis based on the amount of pressure being applied to the correspondingpressure sensitive analog key 104. Thus, open/short mechanical usertoggling control may be advantageously replaced by electrical controlbased on the key pressure applied by a user to provide a similarintermittent alternating high/low signal output without requiring a userto toggle the keys. It will be understood that although the exemplarymicrocontroller of pressure-sensing digital output circuitry 190 of FIG.4A employs 8 digital falling-edge triggered interrupt inputs Port 1(P1.x), and 8 digital outputs Ports 2 (P2.x), it is possible to select adifferent chip(s) to support more pressure sensitive keys.

In addition to digital outputs 133, pressure-sensing digital outputcircuitry 190 also provides a signal 145 corresponding to eachcapacitive pad 231 that indicates the force or extent to which the key104 is depressed to haptics control circuitry 160. In one embodiment,each signal 145 is a digital signal similar to the corresponding digitaloutput signal 133 produced by pressure-sensing digital output circuitry190, i.e., being produced in an intermittent alternating high/low mannerat a variable speed that is based on the amount of pressure beingapplied to the corresponding pressure sensitive analog key 104. However,a pressure indication signal 145 may be any other type of signalsuitable for indicating pressure applied to a corresponding pressuresensitive analog key 104. Haptics control circuitry 160 in turn producesa corresponding haptics control signal 147 to actuate the hapticscircuitry 260 that corresponds to (e.g., is mechanically coupled to orotherwise associated with) the particular pressed key 104. In oneexemplary embodiment, haptics control signal 147 may be operable tocause haptics circuitry 260 to produce a vibration or other type ofmovement for the pressed key 104 that is proportional or otherwisevariable relative to the amount of pressure currently being applied tothe corresponding pressed key 104.

In the illustrated embodiment of FIG. 4A, haptics control circuitry 160may include at least one haptics controller 162 as shown. Although onehaptics controller 162 receiving multiple pressure indication signals145 and producing multiple corresponding haptics control signals 147 isillustrated in FIG. 4A, it will be understood that haptics controlcircuitry 160 may include more than one haptics controller, e.g., withone haptics controller 162 being provided for independently actuatinghaptics circuitry 260 of each separate pressure sensitive key 104. Inthis regard, additional embodiments are illustrated further herein thatshow just a few of the different circuit configurations that arepossible in the implementation of the disclosed systems and methods.

In the exemplary embodiment of FIG. 4A, keyboard system 100 isimplemented to be interchangeable with a legacy USB keyboard forinterconnection with standard 8 bit keyboard controller 110 via astandard 16×8 key matrix 199 with 16 columns×8 rows and native devicedrivers. However, it will be understood that one or more features of thedisclosed systems and methods may be implemented in non-legacy orcustomized keyboard systems, and in any arrangement of one or morecircuitry components as may be suitable for a given application.

In the exemplary embodiment of FIG. 4A, legacy keyboard controller 110has a standard keyboard matrix open/short input 199 provided for the 104keys on a standard keyboard that is arranged as 16 columns by 8 rows, sothat only 24 signals interface with the keyboard controller 110, ratherthan a signal line per key which would require over 100 signals to thekeyboard controller 110. The keyboard controller 110 operates byinitially selecting a single row and applying a logic level 1 to it.There are 16 keys in a column, with only one of those keys intersectingwith the particular row that's at logic 1. To detect if a key is pressedin a row, each column is sequentially grounded. If a key is pressed, itshorts the column to the row, thus causing the row voltage to drop or golow. When the keyboard controller 110 detects the low voltage on theselected row, the pressed key can be determined by the column/rowintersection that was electrically shorted. Once all columns have beenqueried in a single row, the keyboard controller 110 sequences to thenext row, and so on until all rows have been queried, thus sampling thelogic level for every key.

In summary, though a low voltage sense is used to detect a key press innormal keyboard microcontroller operation, an electrical short isrequired at each intersection of the keyboard key matrix 199 to indicatethe press of a key. Thus, a direct alternating high/low digital outputsignal 133 from a microcontroller such as IT MSP430F2111 is incompatiblewith the inputs to such a legacy keyboard controller 110. However, inthe illustrated embodiment, switching circuitry 192 may be provided asan interface between pressure-sensing digital circuitry 190 and legacykeyboard controller 110 for analog keys 104. The purpose of theswitching circuitry 192 is to convert a high/low digital output streaminto a stream of opens/shorts. For example, as shown in FIG. 4A, aseparate optoisolator 180 has been provided for each correspondinganalog key switch location. Examples of such optoisolators include, butare not limited to, AVAGO 4N35 or ACPL-227 optocouplers available fromAvago Technologies of San Jose, Calif.

In the exemplary embodiment of FIG. 4A, each optoisolator 180 providesan electrical control over the make or break (short or open circuit)connection at a given column/row intersection location of keyboardmatrix open/short input 198 for that particular key. This advantageouslyallows analog keys 104 to be implemented with a conventional keyboardmatrix arrangement and legacy keyboard controller 110 (along with itsfirmware and device driver). Further, the implementation of thisembodiment of switching circuitry 192 allows any key (and/or any numberof keys) of a conventional keyboard matrix to be provided with pressuresensing capability.

FIG. 4B illustrates one exemplary embodiment of haptics controlcircuitry 160 as it may be implemented with pressure sensing interfacecircuitry 185, a keyboard controller 110, and haptics actuationcircuitry 260 provided in the form of a piezo transducer or othersuitable haptics actuator. Haptics control circuitry 160 may beimplemented using any circuitry or combination of circuits suitable forcontrolling haptics actuation circuitry 260 based on the amount ofpressure applied to an analog key 104 in a manner as described furtherherein. In one exemplary embodiment, haptics control circuitry 160 mayinclude a haptics controller 162 (e.g., MAX11835 available from Maxim)and a flyback converter (transformer) circuit 420 as shown. In such anembodiment, haptics controller 162 outputs a low voltage (e.g., 3 volt)waveform signal 146 representative of a selected vibration waveform thatcorresponds to the pressure applied to an analog key 104. Optionalflyback converter circuit 420 may be present to amplify the low voltagewaveform signal 146 (e.g., to about 160 volts sawtooth) and to providethis amplified signal 147 to the piezo transducer 260 of hapticsactuation circuitry 260. In the exemplary embodiment of FIG. 4B, hapticscontroller 162 and pressure-sensing digital output circuitry 190 (e.g.,pressure sensing and binning controller) operate in parallel, and alsointeract with each other to enable variable pressure haptics for keys104 using a two-path output signal architecture from pressure-sensingdigital output circuitry 190 (i.e., a trigger/waveform address signalpath 145, and a toggle signal path 133).

As shown in FIG. 4B, haptics controller 162 may include or otherwiseaccess memory 430 (e.g., RAM or any other suitable non-volatile orvolatile memory) that stores one or more vibration waveforms. Forexample, memory of a MAX11835 controller may store up to 16 differentvibration waveforms that are selected to correspond to differentpressure force levels applied to a variable pressure sensitive key 104.Each of the vibration waveforms may be assigned a corresponding waveformaddress in memory of the controller. In operation of PATH 1 (hapticspath) of FIG. 4B, pressure-sensing digital output circuitry 190 mayoutput a pressure indication signal 145 as a falling edge trigger eventto haptics controller 162. The pressure indication signal 145 mayinclude the selected waveform address (e.g., 4 bit waveform address)that corresponds to the desired vibration waveform and current pressurelevel applied to a given key 104. The haptics controller may thenretrieve the selected particular waveform from memory 430 according tothe waveform address, and then output this selected waveform as lowvoltage waveform signal 146 to flyback circuit 420. Duration of signal146 may be of any selected and suitable time, but in one embodiment maybe a short duration waveform signal (e.g., of about 45 milliseconds)that loops or repeats over and over for a period corresponding to apolling period of pressure-sensing digital output circuitry 190 (e.g.,for a period of about ½ second or other greater or lesser time value).

Still referring to FIG. 4B, PATH 2 (toggle path) is implemented by theillustrated components as follows. After the 4 bit waveform of PATH 1 isloaded, key toggling is initiated by pressure-sensing digital outputcircuitry 190 by providing digital signal 133 to keyboard key matrix 199and keyboard controller 110 via optoisolator 180 of output switchingcircuitry 192 in a manner as described elsewhere herein. The rate of thekey toggling of digital signal 133 is dictated by the applied pressurelevel, and toggling occurs for a period corresponding to a pollingperiod of pressure-sensing digital output circuitry 190 (e.g., for aperiod of about ½ second or other greater or lesser time value). In thisregard PATHS 1 and 2 may operate in parallel, although PATH 1 may bestarted first due to the latency of loading in the waveform address viasignal 145.

FIG. 4C illustrates the embodiment of FIG. 4B in more detail, it beingunderstood that in this exemplary embodiment separate haptics controlcircuitry 160 (with a separate haptics controller 162 and flybackcircuit 420) may be provided to receive each corresponding pressureindication (haptics trigger output) signal 145 and to provide arespective haptics control signal to the corresponding hapticstransducer 260 of each haptics enabled key 104. As shown in FIG. 4C, atleast three function blocks may be implemented by pressure-sensingdigital output circuitry 190: block 193 performing sense and measurecapacitance in round-robin cycle; block 195 performing identification ofa particular pressed key 104 and corresponding digital output count; andblock 197 performing determination of pressure level, selection ofvibration waveform, output of the selected waveform for the determinedkey pressure level, and output of the key-toggle rate output rate forthe determined key pressure level. Also illustrated in FIG. 4C isregister 431 provided for haptics controller 162 for purposes of settingparameters and functions internal to the Haptics controller 162 for thedesired functional operation and performance. I2C bus 483 is also shownpresent between pressure sensing interface circuitry 185 and hapticscontrol circuitry 160 for the purpose of initializing the clocks andregisters of the haptics controller 162, as well as providing analternative method of communicating the address of the vibrationwaveform from RAM 430 to the registers 431 in real-time which results inan amplified vibration waveform outputted from the flyback circuit 420to the piezo transducer 260.

FIG. 4D illustrates another exemplary embodiment in which hapticscontrol circuitry 160 may be implemented using a single hapticscontroller 162 to support actuation of multiple haptics transducers 260,e.g., for multiple pressure-sensitive keys 104. In this regard, it willbe understood that similar architecture may also be employed withhaptics control circuits 160 that include more than one hapticscontroller 162, but in which at least one of the multiple hapticscontrollers itself supports more than one haptics transducers 260. Asshown in FIG. 4D, a single common haptics controller 162 of hapticscontrol circuit 160 is coupled to receive a common pressure indicationsignal 145 output by pressure-sensing digital output circuitry 190whenever any one of the multiple variable pressure sensitive keys 104are pressed. This common pressure indication signal 145 indicates theforce or extent to which any one of the given multiple keys 104 (i.e.,one of keys 1-n) is currently pressed. Haptics controller 162 thenprovides a corresponding low voltage waveform signal 146 to flybackcircuit 420, which in turn produces a haptics control signal 147 in amanner as described elsewhere herein.

In the exemplary embodiment of FIG. 4D, only a single haptics controlsignal 147 is generated for controlling any given one of the multiplehaptics transducers 260 corresponding to multiple analog keys 104. Inthis regard, pressure-sensing digital output circuitry 190 controlsactuation of only the appropriate haptics transducer 260 thatcorresponds to the currently-pressed analog key 104 by generating anappropriate haptics enable signal 462 to switch on the respectivehaptics control switch 464 (e.g., MOSFET such as SiA456DJS availablefrom Vishay of Shelton, Conn.) corresponding to the haptics transducer260 of the appropriate pressed key 104. Since only one haptics controlswitch 464 is switched on at any given time by pressure-sensing digitaloutput circuitry 190, haptics motion is only provided by the hapticscontrol signal 147 to the transducer 260 of the key 104 being currentlypressed. FIG. 4D further illustrates that pressure-sensing digitaloutput circuitry 190 is also configured to provide a separatealternating high and low (high/low) digital output bit stream signal 133for each variable pressure sensing key 104 for output switchingcircuitry 192 in a manner as described elsewhere herein. It will beunderstood that pressure-sensing digital output circuitry 190 may beconfigured as desired or needed to arbitrate between multiple analogkeys 104 that are pressed simultaneously in a system configuredaccording to the exemplary embodiment of FIG. 2D, e.g., so that thehardest pressed analog key 104 at any given time is provided withhaptics motion, so that the most lightly pressed analog key 104 at anygiven time is provided with haptics motion, so that the analog key 104continuously pressed for the longest duration is provided with hapticsmotion (i.e., the first pressed analog key 104 of simultaneously-pressedanalog keys 104 is provided with haptics motion), etc.

FIG. 4D also shows exemplary details of a MAXIM-specified flybackconverter circuit 420 that may be employed in one embodiment, it beingunderstood that other flyback converter circuit and/or transformercircuit configurations are possible. In particular, MAXIM-specifiedflyback converter circuit 420 of this exemplary embodiment includes a1:10 transformer 476 (e.g., LDT565 available from TDK Corporation ofTokyo, Japan) that is coupled to receive low voltage waveform signal 146and efficiently amplify it to produce a high voltage haptics controlsignal 147. Boost secondary current-sense input 470 couples to secondaryside of transformer 476 for purposes of current measurement by thehaptics controller 162. As shown, a diode 477 (e.g., BAS321 generalpurpose diode available from NXP Semiconductor of Eindhoven,Netherlands) may be provided at the secondary side of transformer 476for rectification along with prevention of reverse surge. A 4.99K ohmresistor 479 is present between piezo transducer 260 and diode 477 andis a filter resistor used to reduce audible noise. A 47 nF capacitor478, coupled to ground is connected at a node C between resistor 479 anddiode 477, is a reservoir cap that internal DC-DC converter dumps chargeto. The value may also be modified according to the waveform beingdriven. Haptics controller 162 is also coupled by a separate signal line472 and 2 M ohm resistor 471 to a node A positioned between resistor 479and diode 477. The output voltage at nodes A, B and C, is sampled by thehaptics controller 162 on analog feedback input signal 472 via resistivevoltage divider which is composed of 2M ohm resistor 471 and 27K ohmresistor 473. The analog input signal 472 is sampled by an A/D converterinternal to the haptics controller. Based on the A/D conversion and theparticular vibration waveform pattern selected to output, either thevoltage boost is turned on or the current sink, based on MOSFET (Vishaypn SIA456DJ) 475, is turned on.

FIG. 5 illustrates one exemplary embodiment of methodology 500 that maybe employed for initialization of pressure-sensing digital outputcircuitry 190 of keyboard system 100 of FIG. 4. As shown, methodology500 starts in step 502 with power up of an information handling systemto which keyboard system 100 is coupled. The watchdog timer is stoppedin step 504, and timer speed (e.g., digitally controlled crystaloscillator speed) is set in step 506 (e.g., to 16 MHz for TI MSP430F2111microcontroller). Note that the faster the Timer's clock (e.g., DCO) isrunning, the more accurate the timing measurement of the RC discharge.Next, in optional step 508, any embedded low frequency crystaloscillator when present (e.g., such as is the case with the TIMSP430F2111) is turned off because the I/O pins for this oscillator canalso function as I/O pins for additional capacitive pads supportingnegative edge triggered interrupts. In such a case these oscillator pinsmay be optionally used as I/O pins to keep the package size (and pin outcount) of the microcontroller as small as possible. Further, since thereis no need for any additional clocks, any on-board low speed clock maybe disabled in order to reduce power consumption and eliminate anunnecessary source of electrical noise. In step 510, all I/O pins ofpressure-sensing digital output circuitry 190 are initialized to outputmode and logic “0” (ground). Then in step 512, all analog pressuresensitive keys 104 are scanned, one at a time in a sequential orround-robin fashion, by measuring the voltage of each analog key 104while all other analog keys are grounded. It does this by operating assuch:

-   -   1. The I/O pin is set to output high. A Timer is read to mark        the start time.    -   2. The I/O pin is set to input mode with negative edge interrupt        enabled. The resistor then discharges the capacitive pad. The TI        MSP430 microcontroller goes into low power mode for reduced        power consumption, however, it's still able to monitor the        interrupt enabled input I/O pins.    -   3. When the voltage of the sensor crosses the low level voltage        threshold, an interrupt is generated.    -   4. The interrupt service routine (ISR) reads the Timer and        calculates the time to discharge to the low voltage threshold        level. This is referred to as a “count” value. The MSP430 exits        low power mode and continues operation.

In one embodiment, upon host boot-up, a measurement of each of theanalog keys may be performed sequentially (“scanning process”) aslabeled in step 512. This scanning process may be performed multipletimes (e.g., 100 times) in order to allow the master clock and PCBconditions to stabilize.

Though not required, for some applications it may be advisable toprovide additional filtering of the “count” measurement to remove anyresidual noise and further increase sensitivity of the capacitive padsas capacitive pad measurements are often noisy due to a number offactors such as temperature, humidity, voltage drift, componenttolerances and 50/60 Hz mains. In step 514, a base capacitance isestablished and tracked, as the base capacitance of the capacitive padcan change due to environmental conditions such as temperature,humidity, voltage drift and/or component tolerances. Note that this is aslow type of change as changes occur in minutes, not microseconds. Abaseline capacitance is established as the capacitance of each padduring the open state (when no finger is pressing on the key). As any ofthe above mentioned environmental factors changes, the base capacitancefor each pad is updated and stored. If a decrease in capacitance isdetected, the software must adjust the base capacitance rapidly sincethis is not a function of the sensor excitation. We can do this bere-averaging with the current count result. If an increase incapacitance is detected, the base capacitance may be adjusted veryslowly as this may be due to a finger hovering over a key, and notbecause of an environmental drift effect. For example, the basecapacitance may be adjusted by 1 with each measurement, but only if nokeys are pressed. Additionally, an optional low pass filter (e.g.,implemented in firmware/software or otherwise), may also help toeliminate the presence of any 50/60 Hz main-power noise that may becoupled onto the capacitive pads. For example, in one exemplaryembodiment, the low pass noise filter may be implemented as a softwarebased IIR (infinite impulse response) filter, or essentially as a DCtracking filter.

Finally, in step 516, sensing for user pressure on each of analog keys104 is started. The endless loop of this sensing process is describedfurther below in relation to FIG. 6A and FIG. 6B.

FIG. 6A illustrates methodology 600 for sensing, in real time, pressureapplied to analog keys 104, and producing a toggled (alternatingopen/short) digital signal 133 representative thereof. FIG. 6A starts instep 602 by taking an averaged capacitance measurement for each pressuresensitive key 104 from signals 131 based on timer counts in a roundrobin manner as previously described. This may be done by actuallytaking multiple (e.g., two) measurements at a given pad. If thesemultiple measurements are conducted in quick succession, the averagebehaves like a differential measurement, thus helping filter outcommon-mode noise. Next, in step 604, the baseline count may beevaluated and updated per pad, as per the rules described above, and runthrough the low pass filter to generate a filtered count output (alsocalled the adjusted capacitance measurement). In step 606, the presentadjusted capacitance measurement value for each key 104 is then stored,e.g., in memory of pressure-sensing digital output circuitry 190. Next,in step 608, all the stored present adjusted capacitance values areexamined to determine key(s) 104 having a present value of adjustedcapacitance that exceeds a pre-determined adjusted capacitance threshold(this is the currently pressed key(s) 104). Then in step 610 the presentidentity (e.g., key number) of each of the key(s) 104 meeting thethreshold adjusted capacitance value is stored along with correspondingpresent capacitance value(s). Alternatively, the key 104 being currentlypressed may be identified as the key 104 having the largest adjustedcapacitance measurement of all keys 104 in the current round robincycle, i.e., rather than using the adjusted capacitance threshold valueto determine pressed keys.

Example code for executing steps 602-610 is as follows:

/* TAKE MEASUREMENT ON 4 CAPACITIVE PADS */ int scan_keys(void) {  inti;  int margin;  for (i = 0; i < NUM_LINES; i++)  {   /* take padmeasurement and establish */   margin = measure_key_capacitance(i) −  key_line[i].base_capacitance;   /* convert measurement to filteredvalue using a single pole IIR   low pass   filter */  key_line[i].filtered += (margin − (key_line[i].filtered >> 4));   /*KEY_LINE[I].FILTERED IS OUR “COUNT” WE WANT   TO USE */  }  return 0; }/* FIGURE OUT WHICH KEY LINE IS PRESSED ON (IF ANY) */ intfind_finger_position(void) {  int i;  int min;  int max;  int max_pos;/* Find the minimum and maximum responses for all the 4 key lines */ min= 32767; max = −32768; max_pos = −1; for (i = 0; i < NUM_LINES; i++) { if (key_line[i].filtered < min)   min = key_line[i].filtered;  if(key_line[i].filtered > max)  {   max = key_line[i].filtered;   max_pos= i;  } } /* If the maximum response isn't that big, there is no fingerpresent. */ if (max < 200) {  P1OUT &= 0xCF; /* no key pressed = “00”(P1.5, P1.4) */  P1DIR |= 0x30;  return 0; } /*P1.5, P1.4 are the 2 bitoutput pins*/ /* TRUTH TABLE BELOW FOR KEY PRESS */ /* P1.5 P1.4  0   0 NO KEY IS PRESSED  1   0  P1.0 IS PRESSED  1   1  P1.2 IS PRESSED  0  1  P1.3 IS PRESSED */ if (max_pos == 0) {  P1OUT |= 0x20; /* P1.0 ISPRESSED = “10” */  P1OUT &= 0xEF;  P1DIR |= 0x30;  return max; } if(max_pos == 2) {  P1OUT |= 0x30; /* P1.2 IS PRESSED = “11” */  P1DIR |=0x30;  return max; } if (max_pos == 3) {  P1OUT &= 0xDF; /* P1.3 ISPRESSED = “01” */  P1OUT |= 0x10;  P1DIR |= 0x30;   return max;  }  if(max_pos == 1)  {   P1OUT &= 0xCF; /* otherwise = “00” */   P1DIR |=0x30;   return 0;  }  else  {   P1OUT &= 0xCF; /* otherwise = “00” */  P1DIR |= 0x30;   return 0;  } } int pressed_key_pressure = 0; voidmain(void) { . . . /* INITIALIZE ALL PADS TO BE SCANNED TO GROUND */ for (i = 0; i < NUM_LINES; i++)   init_key(&key_line[i],&key_line_config[i]);  TACTL = TASSEL_2 | MC_2; // | ID_3;  /* Scan thekeys 100 times, allowing plenty of time for the MCLK and  boardconditions to stablise */  for (i = 0; i < 100; i++)   scan_keys( );  /*Establish base capacitance and filtered “count” per active pad */  for(i = 0; i < NUM_LINES; i++)  {   key_line[i].base_capacitance =key_line[i].filtered >> 4;   key_line[i].filtered = 0;  }  for (;;)  {  scan_keys( );   if ((pressed_key_pressure = find_finger_position( )) >0)   {    /* There is a finger on the pad */   send_to_host(pressed_key_pressure);   }   else   {    /* There is nofinger on the pad */    send_to_host(0);   }  } }

Still referring to FIG. 6A, the degree of applied pressure to apresently-pressed key is next determined, e.g., in a binning operationby comparing the filtered count value to a pre-determined scale ofcounts per resolution in step 612 based on the stored adjustedcapacitance value (or filtered count value) of step 610.

For example, in one exemplary embodiment, four levels of differenttoggle output resolution (i.e., alternating toggle rate frequency) maybe pre-defined for measured timer counts of a pressed key 104. As anexample, a maximum toggle rate may be defined to correspond to a maximumtimer count level of 200 with four decreasingly lower toggle rate levelsdefined for timer counts of 180, 160, 140 and 120, and anything lessthan or equal to 120 being disregarded as noise, e.g., toggle ratefrequency of 20 times/second for timer count range of anything greaterthan 180 up to 200, toggle rate frequency of 16 times/second for timercount range of anything greater than 160 up to 180, toggle ratefrequency of 10 times/second for timer count range of anything greaterthan 140 up to 160, toggle rate frequency of 8 times/second for timercount range of anything greater than 120 up to 140, and no toggling fortimer count range of less than or equal to 120. This example toggleoutput scheme may be expressed as follows:

pressure level 4: count>180

pressure level 3: 160<count<=180

pressure level 2: 140<count<=160

pressure level 1: 120<count<=140

pressure level 0 (do nothing): anything else

However, it will be understood that this particular number of timercount levels and corresponding timer count values is exemplary only andthat greater or fewer numbers of timer count levels and/or differenttimer count values may be employed in other embodiments.

Following is example code for the four timer count level embodimentdescribed above:

if (count > 180)   for (num_toggles = 20; num_toggles >0 ;num_toggles−−)    {    P2OUT {circumflex over ( )}= 0x02;    /*ToggleP2.1 low 10 times in 1 sec */    /* loop provides delay of 0.05sec/.000017922 sec = 2789 loops */    for (loop=2789; loop>0; loop − −);   } else if ((count > 160) && (count <= 180))   for (num_toggles=16;num_toggles>0; num_toggles − −)    {    P2OUT {circumflex over ( )}=0x02;    /*Toggle P2.1 low 8 times in 1 sec */    /* loop provides delayof 0.0625 sec/.000017922 sec =    3487 loops */    for (loop=3487;loop>0; loop − −);    } else if ((count > 140) && (count <= 160))   for(num_toggles=10; num_toggles>0; num_toggles − −)    {    P2OUT{circumflex over ( )}= 0x02;    /*Toggle P2.1 low 5 times in 1 sec */   /* loop provides delay of 0.1 sec/.000017922 sec = 5579 loops */   for (loop=5579; loop>0; loop − −);    } else if ((count > 120) &&(count <= 140))   for (num_toggles=4; num_toggles>0; num_toggles − −)   {    P2OUT {circumflex over ( )}= 0x02;    /*Toggle P2.1 low 2 timesin 1 sec */    /*loop provides delay of 0.25 sec/.000017922 sec =13949loops */    for (loop=13949; loop>0; loop − −);    } else    {    / * DONOTHING. KEY IS NOT PRESSED ON */    }

It will be understood that step 610 described above is optional and onlymay be employed when the number of analog keys 104 exceeds the number ofoutput lines 133. Alternatively, methodology 600 may: pause the roundrobin measurements whenever a pressed key 104 is identified as exceedingthe threshold adjusted capacitance value, determine the degree ofapplied pressure to pressed key 104 based on its capacitance, and togglethe output signal of the pressed key 104. The count value of theidentified pressed key 104 may be monitored and reevaluated for as longas it remains pressed by reevaluating the pressed key's timer count byrerunning it through the binning operation to see if the pressure ischanged, and outputting an updated digital bit stream signal 133 basedthereon. Once it is determined that the identified key 104 is no longerbeing pressed, then the round robin procedure may resume to the next key104 and inquire of its count value for this round robin cycle. Eitherway, the round robin cycle continues for as long as the keyboard system100 is powered up. After shut down, the pressure-sensing digital outputcircuitry 190 may be reset on next power up, all keys reinitialized(e.g., per FIG. 5), and the round robin key capacitance measurementroutine initialized again.

In steps 614 to 620 of methodology 600, the haptics vibration waveformand toggle rate is selected based on the determined key pressure of step612 which is sensed by pressure-sensing digital output circuitry 190based on the key capacitance value (e.g., each variable pressure key 104generates a variable capacitance with the capacitance value increasingas a user applies greater finger pressure to the key 104). As describedelsewhere herein, pressure-sensing digital output circuitry 190generates a digital count value that increases with increasedcapacitance, and a value that identifies which key 104 is currentlybeing pressed. Thus, at the start of the binning operation, the digitalcount and the pressed key identifier values are known.

Once the pressed key identifier value has been processed, the digitalcount value is then sorted in steps 614 to 620 of FIG. 6A to determinethe amount of pressure applied (e.g., on a scale of 1 to 10, 1 to 4, orany other acceptable or selected range of pressure resolution that hasbeen programmed). In one exemplary embodiment, this pressure resolutionvalue range may be programmable by the user using a software graphicaluser interface (GUI) utility. In the exemplary embodiment of FIG. 6A,methodology for a pressure scale of 1 to 4 is illustrated, wherepressure level 1 is associated with light finger pressure and pressurelevel 4 is associated with max finger pressure. A digital count value ofless than 120 is taken to indicate that the respective key 104 has notbeen pressed hard enough to make an electrical “make” connection, whilea digital count value greater than 180 indicates maximum finger pressurehas been applied to the respective key 104. The separate pressure levelsof 1, 2, 3 and 4 are defined in this embodiment by four equal 25%increments between the minimum and maximum pressure levels to definefour levels of finger pressure, it being understood that equalincrements are not required.

Still referring to FIG. 6A, if the measured timer counts of a pressedkey 104 is determined to exceed 180 in step 614, then methodology 600proceeds to step 622 where pressure-sensing digital output circuitry 190applies a falling edge trigger and writes to haptics controller 162 anaddress pointer corresponding to the appropriate haptics vibrationwaveform (e.g. “waveform 4”), previously stored in RAM 430 uponpower-up, corresponding to pressure level 4, on Haptics Trigger outputsignal 145 for respective pressed key 104. Also in step 622, thepressure-sensing digital output circuitry 190 enables the respective KeyHaptics Enable output signal to turn on the respective output MOSFET 464to enable vibration on the respective piezo transducer 160 for theanalog key 104 that's being pressed on. In such an example, methodology600 then proceeds to step 624 where a low active toggle output 133 ofpressure-sensing digital output circuitry 190 is toggled thatcorresponds to the identity of the presently-pressed key (e.g., outputP2.1 is toggled for corresponding input P1.1). This toggled signalmimics or emulates the action of a user repeatedly pressing aconventional digital key 106 for a number of times that is proportionalor otherwise relative to the strength of the desired input (i.e. greaterpressure on analog key 104 corresponds to more rapid user repeat rate ondigital key 106). Thereafter, once the Haptics controller 162 notifiesthe Pressure Sensing & Binning Controller 190 that it's done outputtingthe vibration waveform from RAM, controller 190 deactivates the HapticsTrigger output 145, the respective Key Haptics Enable output 462, andthe Toggle output 133. This assures no possible race condition orcondition where controller 190 is accidentally deactivating vibrationactivity to the key prematurely. Controller 190 then resamples thelatest key pressure level and identity of currently-pressed key outputat step 612 and re-evaluates the degree of pressure applied again insteps 614 to 620.

If the measured timer counts of a pressed key 104 is determined not toexceed 180 in step 614, then methodology 600 proceeds to step 616 wherepressure-sensing digital output circuitry 190 determines if the numberof measured timer counts of pressed key 104 is between 160 and 180. Ifso, then methodology 600 proceeds to step 628 where circuitry 190generates a falling edge trigger for haptics controller 162 and alsowrites to haptics controller 162 on Haptics Trigger output 145 anaddress pointer corresponding to the appropriate haptics vibrationwaveform (e.g. “waveform 3”), previously stored in RAM 430 uponpower-up, corresponding to pressure level 3 for this count range,enables the respective Key Haptics Enable output 462, and toggles lowactive output 133 of pressure-sensing digital output circuitry 190 tothe identity of the presently-pressed key using a toggle signal that isproportional or otherwise relative to the strength of the desired inputbefore resetting toggle line 133 and repeating back to step 614 in amanner similar to steps 622 to 626. A similar methodology is implementedby each of steps 618/630 and 620/632 for respective measured timer countranges of greater than 140 up to 160 and greater than 120 up to 140,corresponding to pressure levels 2 and 1 as shown. If measured timercount is less than 120 (interpreted in this embodiment as being noapplied pressure) in step 627 then methodology 600 returns to step 602as shown.

FIG. 6B also illustrates exemplary methodology 700 that may beimplemented, for example, by haptics controller 162. As shown in FIG.6B, haptics controller 162 is first initialized in steps 752 to 756, atthe same time that clocks, resets and registers of pressure-sensingdigital output circuitry 190 are initialized. These initializationactions for both controllers 190 and 162 may occur upon power up of thesystem. In the case of FIG. 6B, clocks and registers of hapticscontroller 162 are initialized in step 752. In the haptics controller162, these registers are used to control waveform shape, period, andplayback attributes such as looping the waveform for a particular timeduration. Then multiple haptics vibration waveforms (e.g., 16 waveformsin the case of Maxim MAX11835 Rev. 2 chip) are loaded into memory (e.g.,RAM 430) of haptics controller in step 754, prior to putting thecontroller circuitry into low power mode in step 756. During this lowpower mode, a waveform trigger input of haptics controller 162 is active(awake) and waiting for a suitable trigger event (e.g., falling edgetrigger event) from pressure-sensing digital output circuitry 190 onHaptics Trigger output signal 145.

Next, haptics controller 162 begins steps 758 to 762. In step 758,haptics controller receives a falling edge trigger and waveform addressfrom Haptics Trigger output signal 145 from step 622 of pressure-sensingdigital output circuitry 190. The falling edge trigger, along with somepreset registers in the haptics controller, notifies the hapticscontroller 162 that it needs to grab a particular vibration waveformfrom RAM that corresponds to the pressure level determined in step 612,and output the waveform (e.g., waveform 4) to the flyback circuit 420which is then outputted with a high voltage to the piezo transducer 260.The output of step 622 ensures that the Key Haptics Enable signal 462 isactive which activates output MOSFET 464 to ensure the respective piezotransducer 260 receives the high voltage output signal 147 from theflyback circuit 420. In one exemplary embodiment, the waveform stored inRAM may last about 45 milliseconds. In such a case, in step 760, theselected waveform is looped and repeated for a selected duration (e.g.,for about 0.5 seconds). It will be understood that this duration may besmaller or larger as the user chooses. In one exemplary embodiment, thevibration waveform loop/repeat time duration in Step 760 may be selectedto be smaller than that of the toggling time duration in step 624 inorder to prevent a possible race condition. In this regard, it isdesirable that that step 762 is met (vibration completed) before step626 takes effect in order to ensure that the vibration and MOSFETselection switch does not turn off prematurely.

Step 762 occurs at a stage where the waveform output of 0.5 secondduration has been completed. In step 762, the Haptics Controller 162enters a low power or sleep mode, and waits for the next trigger fromstep 622. In parallel, step 626 verifies that step 762 is completed andhas the pressure sensing controller deactivate (or reset) the HapticsTrigger output 145, the Key Haptics Enable 462 and the Toggle output133. Methodology 700 then returns to step 758 where the next fallingedge trigger and waveform address pointer is received frompressure-sensing digital output circuitry 190. Thus, in this exemplaryembodiment, both the haptics vibration and key toggling occur for aparticular finger pressure for a period of 0.5 second before the keysare resampled, evaluated, and the count and pressure level areredetermined before changing to a new vibration and toggling to occur inthe next 0.5 seconds. Again, the period may be reduced to something lessthan 0.5 seconds to be more responsive (less latency) to changes infinger pressure on the analog key 104.

Thus, FIGS. 6A and 6B illustrate how two actions may be performed inparallel once a key pressure level match is made by pressure-sensingdigital output circuitry 190. The first action is that the hapticsvibration waveform is output from pressure-sensing digital outputcircuitry 190 to the haptics circuitry 260 (e.g., piezo transducer)coupled to (e.g., mounted under) the pressed key at a vibrationintensity that corresponds to the pressure level. This is accomplishedby sending a falling edge trigger to the haptics controller 162 to wakeit up from sleep, and by writing the waveform address for the givenpressure level to the haptics controller 162. Then the applicable outputMOSFET 464 is activated so the applicable piezo transducer 260 canreceive the waveform in order to vibrate. The haptics controller 162immediately outputs the waveform to the haptics circuitry 260, e.g.,continuously for ½ seconds or any other selected suitable duration. Oncethe duration of the haptics vibration waveform output is completed, thehaptics controller 162 goes back to low power mode, and thepressure-sensing digital output circuitry 190 resets the trigger line,the key haptics enable line and the toggle line so the hapticscontroller 162 is ready to receive the next falling edge trigger event.

The waveform address write operation may be performed using any suitablemethodology, including using I2C bus signals. However, in one exemplaryembodiment, the address write may be performed in as few clock cycles aspossible to reduce the latency from the applied finger pressure to theresulting key vibration. For example, where a Maxim MAX11835 Rev. 2 chipis employed as haptics controller 162, a feature of this chip called“multi-wave” mode may be utilized to directly write the 4 bit waveformaddress serially from the pressure-sensing digital output circuitry 190to the haptics controller chip in a fraction of the time required by I2Cbus communications.

The second action performed in parallel is that circuitry associatedwith the pressed key 104 is electronically toggled at a rate thatcorresponds to the pressure level applied to the pressed key 104. In oneembodiment, once the waveform address has been written to the hapticscontroller 162, the pressed key's signal line 133 is toggled at a ratecorresponding to the particular pressure level. In this way, keytoggling action and its respective key vibration action operate inparallel to provide a user the feeling that both are operating insynchronization with each other. At the completion of the key togglingaction, the falling edge trigger signal, the output MOSFET enable line462 and toggle line 133 are set to an inactive state. The latest digitalcount and key identifier values from the pressure-sensing digital outputcircuitry 190 are then re-sampled to determine if there have been anychanges in key pressure status and if so, to execute vibration andtoggling actions based on the updated key pressure status. The resultingeffect is that the vibration intensity of a given key 104 and itscorresponding key toggling speed will vary according to real-timeapplied finger pressure to the particular key 104.

It will be understood that methodologies 600 and 700 of FIGS. 6A and 6Bare exemplary only, and that methodologies employing additional, fewer,and/or alternative steps may be employed that are suitable forimplementing one or more of the features described herein.

EXAMPLE

The following example represent illustrative and exemplary piezo input(haptics vibration waveforms) that may be sent to the piezotransducer(s)to provide a progressive increase in intensity as a userpresses harder on a variable pressure sensitive key, it being understoodthat alternative piezo input waveforms, and/or number of separatewaveforms, may be employed.

The waveforms of this example may be used with a variable pressurekeyboard supporting four levels of sensitivity. In this example, eachkey pressure level has a unique toggle output as well as a unique piezovibration waveform. Four vibration waveforms are provided, one for eachpressure level, to vibrate a pressed key progressively from a lightvibration to a rough/intense vibration.

FIGS. 7-10 illustrate the four different haptics vibration waveforms ofthis example. The shape, amplitude, and period of each waveform arestored in RAM memory 430 of a MAX11835 haptics controller chip. Firmwareimplementing methodologies 600 and 700 described elsewhere herein isused to sense what key pressure level is currently in effect, to selectthe appropriate vibration waveform for that pressure level, and to startoutputting the waveform while in parallel outputting the key togglingsignal. The four illustrated vibration waveforms provide a progressiveincrease in vibration intensity felt starting with FIG. 7 and increasingto FIG. 10.

A commonality may be seen with respect to the four waveforms of thisexample: their period is always 64 ms, the sawtooth pulse lasts 10 msec,and the amplitude of the sawtooth pulse remains the same regardless ofintensity level. What varies is how many sawtooth pulses are outputtedwithin the 64 ms window. As the number of sawtooth pulses outputting inrapid succession is increased, the intensity of the vibration increases.

It will be understood that one or more of the tasks, functions, ormethodologies described herein may be implemented, for example, asfirmware or other computer program of instructions embodied in anon-transitory tangible computer readable medium that is executed by aCPU, controller, microcontroller, processor, microprocessor, FPGA, ASIC,or other suitable processing device.

Further modifications and alternative embodiments of the techniquesdescribed herein will be apparent to those skilled in the art in view ofthis description. It will be recognized, therefore, that the techniquesdescribed herein are not limited by these example arrangements.Accordingly, this description is to be construed as illustrative onlyand is for the purpose of teaching those skilled in the art the mannerof carrying out the techniques described herein. It is to be understoodthat the forms of the techniques described herein shown and describedare to be taken as the presently preferred embodiments. Various changesmay be made in the implementations and architectures. For example,equivalent elements may be substituted for those illustrated anddescribed herein and certain features of the techniques described hereinmay be utilized independently of the use of other features, all as wouldbe apparent to one skilled in the art after having the benefit of thisdescription of the techniques.

The invention claimed is:
 1. A keyboard system, comprising: one or morepressure sensitive keys configured to provide analog output signalscorresponding to each given one of the pressure sensitive keys that isrepresentative of the level of pressure applied to the given key duringa key pressure application event of a given applied pressure level; afirst controller configured as pressure sensing interface circuitrycomprising at least one signal input, at least one first signal output,and at least one second signal output, the signal input being separateand different from the first signal path output and the second signalpath output, the first signal path output being different from thesignal input and the second signal output, and the second signal pathoutput being different from the signal input and the first signaloutput; where the signal input is coupled to receive the analog outputsignal from each given one of the pressure sensitive keys via at leastone dedicated input signal path; where the pressure-sensing interfacecircuitry is configured to simultaneously provide both haptics keypressure indication signals at the first signal path output to at leastone first separate dedicated output signal path and separate digital keyemulation key pressure indication signals at the separate second signaloutput to at least one second separate dedicated output signal path andresponsive to each of the same analog output signals received at thesignal input from a given one of the pressure sensitive keys thatcorresponds to a given key pressure application event applied to thecorresponding same given one of the pressure sensitive keys, the hapticskey pressure indication signals and separate digital key emulation keypressure indication signals both being representative of at least tworespective different levels of pressure applied to the correspondinggiven one of the pressure sensitive keys, the at least two differentlevels of pressure comprising at least first and second different levelsof pressure; and a second controller different from the firstcontroller, the second controller being configured as haptics controlcircuitry coupled and configured to impart a variable haptics motioncharacteristic independently to each given one of the pressure sensitivekeys in response to each given key pressure application event based atleast in part on the haptics key pressure indication signals provided bythe pressure sensing interface circuitry across the first separatededicated output signal path and corresponding to the pressure levelapplied to the corresponding given one of the pressure sensitive keysduring each given key pressure application event such that a firsthaptics motion is imparted to a given one of the pressure sensitive keysat the first pressure level applied during a first key pressureapplication event to the given one of the pressure sensitive keys thatis different than a second haptics motion that is imparted to the givenone of the pressure sensitive keys at the second pressure level appliedduring a second and different key pressure application event to thegiven one of the pressure sensitive keys; and where the pressure sensinginterface circuitry is coupled to provide the haptics key pressureindication signals across the first separate dedicated output signalpath and to the haptics control circuitry in response to the given keypressure application events; arid where the second signal output of thepressure sensing interface circuitry is configured for coupling by thesecond separate dedicated output signal path to provide a digital keyemulation key pressure indication signal corresponding to a given keypressure application event to a third controller configured as akeyboard controller coupled to a separate host system device and that isseparate and different from the controllers of the haptics controlcircuitry and the pressure sensing interface circuitry at the same timethat the first signal output of the pressure sensing interface circuitryprovides a separate haptics key pressure indication signal correspondingto the same given key pressure application event across the firstseparate dedicated output signal path to the haptics control circuitry;where each of the respective digital key emulation key pressureindication signals is a separate intermittent alternating open and short(open/short) digital output signal having an alternating togglingfrequency that is representative of pressure applied to thecorresponding given one of the pressure sensitive keys to emulatetoggling of a momentary on/off digital key by a user at the alternatingtoggling frequency during the duration of a given key pressureapplication event of a given applied pressure level without requiring auser to toggle the pressure sensitive key; and where the pressuresensing interface circuitry is configured for coupling to provide eachdigital key emulation key pressure indication signal as a separatealternating open/short digital output signal corresponding to eachpressure sensitive key to column/row intersections of a legacy keyboardkey matrix when the legacy keyboard matrix is operably coupled to alegacy digital keyboard controller having no analog input circuitry andwhen the legacy digital keyboard controller is itself coupled betweenthe pressure sensing interface circuitry and a separate host systemdevice to measure keyboard input for the host device based on receivedmomentary-on digital signals and not based on received analog signals.2. The keyboard system of claim 1, further comprising: haptics actuationcircuitry coupled to the haptics control circuitry; where the hapticscontrol circuitry is separate from the keyboard controller and thepressure sensing interface circuitry, the haptics control circuitrybeing coupled to receive from the pressure sensing interface circuitry arespective haptics key pressure indication signal representative ofpressure applied to each corresponding given one of the pressuresensitive keys during each key pressure application event, the hapticscontrol circuitry being configured to in turn provide a separate hapticscontrol signal corresponding to each given one of the pressure sensitivekeys based upon each respective haptics key pressure indication signalreceived during each corresponding key pressure application event; andwhere the haptics actuation circuitry is coupled to receive from thehaptics control circuitry the separate haptics control signalcorresponding to each given one of the pressure sensitive keys, thehaptics actuation circuitry being configured to impart haptics motionindependently to each given one of the pressure sensitive keys inresponse to a received haptics control signal corresponding to the givenone of the pressure sensitive keys.
 3. The keyboard system of claim 2,and where the pressure sensing interface circuitry is further configuredto provide to the haptics control circuitry a haptics key pressureindication signal corresponding to each given one of the pressuresensitive keys as a bit stream that is representative of the pressurebeing applied to the corresponding given one of the pressure sensitivekeys during the duration of a given key pressure application event andat the same time that the pressure sensing interface circuitry providesto a keyboard controller that is separate from the haptics controlcircuitry a digital key emulation key pressure indication signal duringthe duration of the same given key pressure application event.
 4. Thekeyboard system of claim 3, further comprising a keyboard device bodythat includes the pressure sensing interface circuitry, the hapticscontrol circuitry and the haptics actuation circuitry; wherein thekeyboard device body is configured to be mechanically coupled as adrop-in keyboard to an information handling system chassis that includesthe legacy keyboard controller.
 5. The keyboard system of claim 4,wherein the information handling system comprises a notebook computer.6. The keyboard system of claim 1, further comprising a keyboard devicebody that includes the one or more pressure sensitive keys and aplurality of digital keys within the keyboard device body, each of thedigital keys being coupled to provide a single open/short digital outputsignal each time the digital key is pressed by a user.
 7. The keyboardsystem of claim 2, wherein the haptics control signal corresponding toeach given one of the pressure sensitive keys is a vibration waveformhaving at least one of a vibration intensity or frequency correspondingto the pressure level being applied in real time to the correspondinggiven one of the pressure sensitive keys.
 8. The keyboard system ofclaim 7, further comprising memory having multiple vibration waveformsstored therein that are selected to correspond to different pressureforce levels applied to the pressure level being applied in real time tothe corresponding given one of the pressure sensitive keys; wherein thehaptics control circuitry is configured to respond to receipt of ahaptics key pressure indication signal provided by the pressure sensinginterface circuitry that is representative of the level of pressurebeing applied to the corresponding given one of the pressure sensitivekeys by retrieving from memory the selected vibration waveformcorresponding to the pressure level being applied in real time to thecorresponding given one of the pressure sensitive keys, and to providethe selected vibration waveform as the separate haptics control signalto the haptics actuation circuitry; and wherein the haptics actuationcircuitry is configured to impart haptics motion according to theselected vibration waveform independently to the corresponding given oneof the pressure sensitive keys being pressed.
 9. The keyboard system ofclaim 8, wherein the haptics key pressure indication signal provided bythe pressure sensing interface circuitry to the haptics controlcircuitry includes the selected waveform memory address that correspondsto the selected vibration waveform corresponding to the pressure levelbeing applied in real time to the corresponding given one of thepressure sensitive keys.
 10. The keyboard system of claim 2, comprisinga plurality of pressure sensitive keys that are each configured toprovide to the pressure sensing interface circuitry a respectiveseparate analog output signal representative of the level of pressurebeing applied to the given pressure sensitive key; where the pressuresensing interface circuitry is configured to provide separate respectivehaptics key pressure indication signals to the haptics control circuitrythat are representative of at least two different levels of pressureapplied to each individual one of the pressure sensitive keys, the atleast two different levels of pressure comprising at least first andsecond different levels of pressure; where the haptics control circuitryis configured to provide to the haptics actuation circuitry a separaterespective haptics control signal corresponding to each given one of thepressure sensitive keys based upon each respective received haptics keypressure indication signal; and where the haptics actuation circuitry isconfigured to separately and independently impart haptics motion to eachof the plurality of pressure sensitive keys with a variable hapticsmotion characteristic based on the applied key pressure level and basedon the identity of the received haptics control signal corresponding toeach given one of the pressure sensitive keys such that a first hapticsmotion is imparted to each given one of the pressure sensitive keys atthe first pressure level applied to the given one of the plurality ofpressure sensitive keys that is different than a second haptics motionthat is imparted to the given one of the plurality of pressure sensitivekeys at the second pressure level applied to the given one of theplurality of pressure sensitive keys.
 11. The keyboard system of claim1, wherein the haptics control circuitry is configured to impart avariable haptics motion characteristic independently to each given oneof the pressure sensitive keys in response to haptics key pressureindication signals that are representative of the at least first andsecond different levels of pressure applied in real time to thecorresponding given one of the pressure sensitive keys, the hapticsmotion imparted to each given one of the pressure sensitive keys inresponse to a haptics key pressure indication signal corresponding tothe first level of pressure applied to the corresponding given one ofthe pressure sensitive keys being different than the haptics motionimparted to each given one of the pressure sensitive keys in response toa haptics key pressure indication signal corresponding to the secondlevel of pressure applied to the corresponding given one of the pressuresensitive keys.
 12. The keyboard system of claim 2, wherein the hapticsactuation circuitry comprises a piezo transducer.
 13. The keyboardsystem of claim 1, where the analog output signal provided to the signalpath input of the pressure sensing interface circuitry comprises anindividual discharge of a capacitive plate of each given analog key;where the separate digital key emulation key pressure indication signalsprovided at the separate second signal output comprise a stream ofopens/shorts corresponding to each given analog key; and where thehaptics key pressure indication signals provided at the first signaloutput comprise a falling edge trigger event.
 14. The keyboard system ofclaim 1, where each given one of the pressure sensitive keys comprises akeycap and separate haptics actuation circuitry, the separate hapticsactuation circuitry for each given keycap comprising a separate piezotransducer coupled to separately vibrate the given keycap.
 15. Thekeyboard system of claim 1, where the pressure sensing interfacecircuitry is a pressure sensing and binning controller.
 16. A method ofimparting haptics motion, comprising: providing one or more pressuresensitive keys; producing an analog output signal for each given one ofthe pressure sensitive keys when depressed during a key pressureapplication event of a given applied pressure level by a user, theanalog output signals being representative of the level of pressureapplied to the given pressure sensitive key by the user; providing eachof the analog output signals to at least one signal input of a firstcontroller configured as pressure sensing interface circuitry; andsimultaneously providing both haptics key pressure indication signalsfrom at least one first signal path output of the pressure sensinginterface circuitry to at least one first separate dedicated outputsignal path and separate digital key emulation key pressure indicationsignals from at least one separate second signal output of the pressuresensing interface circuitry to at least one second dedicated outputsignal path in response to each of the same analog output signalsreceived at the signal input from a given one of the pressure sensitivekeys that corresponds to a given key pressure application event appliedto the corresponding same given one of the pressure sensitive keys, eachhaptics key pressure indication signal and its simultaneous separatedigital key emulation key pressure indication signal both being basedupon the same analog output signal and both the haptics key pressureindication signals and separate digital key emulation key pressureindication signals being representative of at least two respectivedifferent levels of pressure applied to the given pressure sensitive keyby the user, the at least two different levels of pressure comprising atleast first and second different levels of pressure; imparting avariable haptics motion characteristic independently to each given oneof the pressure sensitive keys in response to each given key pressureapplication event based at least in part on a haptics key pressureindication signal provided across the first separate dedicated outputsignal path and that is representative of pressure applied to the givenpressure sensitive key by the user during each given key pressureapplication event such that a first haptics motion is imparted to thegiven one of the pressure sensitive keys at the first pressure levelapplied during a first key pressure application event to the given oneof the pressure sensitive keys that is different than a second hapticsmotion that is imparted to the given one of the pressure sensitive keysat the second pressure level applied during a second and different keypressure application event to the given one of the pressure sensitivekeys; and providing a digital key emulation key pressure indicationsignal corresponding to a given key pressure application event from thesecond signal output to the second dedicated output signal path at thesame time as providing a separate haptics key pressure indication signalcorresponding to the same given key pressure application event to asecond and different controller configured as haptics control circuitryfrom the first signal output to the first dedicated output signal path;and providing each digital key emulation key pressure indication signalas a separate alternating open/short digital output signal correspondingto each pressure sensitive key to column/row intersections of a legacykeyboard key matrix; where the signal path input is coupled to receivethe analog output signal from each given one of the pressure sensitivekeys via at least one dedicated input signal path; where the pressuresensing interface circuitry is coupled to provide the haptics keypressure indication signals across the first separate dedicated outputsignal path and to the haptics control circuitry in response to thegiven key pressure application events; and where the second signaloutput of the pressure sensing interface circuitry is configured forcoupling by the second separate dedicated output signal path to providea digital key emulation key pressure indication signal corresponding toa given key pressure application event to a third controller configuredas a keyboard controller that is separate from the controllers of thehaptics control circuitry and the pressure sensing interface circuitryat the same time that the first signal output of the pressure sensinginterface circuitry provides a separate haptics key pressure indicationsignal corresponding to the same given key pressure application eventacross the first separate dedicated output signal path to the hapticscontrol circuitry; where the signal input is separate and different fromthe first signal path output and the second signal path output, wherethe first signal path output is different from the signal input and thesecond signal output, and where the second signal path output isdifferent from the signal input and the first signal output; where eachof the respective digital key emulation key pressure indication signalsis a separate intermittent alternating open and short (open/short)digital output signal having an alternating toggling frequency that isrepresentative of pressure applied to the corresponding given one of thepressure sensitive keys to emulate toggling of a momentary on/offdigital key by a user at the alternating toggling frequency during theduration of a given key pressure application event of a given appliedpressure level without requiring a user to toggle the pressure sensitivekey; and where the pressure sensing interface circuitry is configuredfor coupling to provide each digital key emulation key pressureindication signal as a separate alternating open/short digital outputsignal corresponding to each pressure sensitive key to column/rowintersections of a legacy keyboard key matrix when the legacy keyboardmatrix is operably coupled to a legacy digital keyboard controllerhaving no analog input circuitry; and where the legacy digital keyboardcontroller is itself coupled between the pressure sensing interfacecircuitry and a separate host system device to measure keyboard inputfor the host device based on received momentary-on digital signals andnot based on received analog signals.
 17. The method of claim 16,further comprising: providing haptics control circuitry and hapticsactuation circuitry; providing pressure-sensing digital interfacecircuitry that is separate from the haptics control circuitry andhaptics actuation circuitry; receiving the analog output signal fromeach given one of the pressure sensitive keys in the pressure-sensinginterface circuitry; simultaneously providing both haptics key pressureindication signals and separate digital key emulation key pressureindication signals from the pressure-sensing interface circuitry, eachof the separate haptics key pressure indication signals and digital keyemulation key pressure indication signals being based upon the samecommon received analog output signal and being representative of atleast two respective different levels of pressure applied to each givencorresponding one of the pressure sensitive keys, the at least twodifferent levels of pressure comprising at least first and seconddifferent levels of pressure; receiving each of the separate haptics keypressure indication signals in the haptics control circuitry andproviding a separate haptics control signal corresponding to each givenone of the pressure sensitive keys based upon each respective receivedhaptics key pressure indication signal; receiving each separate hapticscontrol signal in the haptics actuation circuitry, and imparting avariable haptics motion characteristic independently to each given oneof the pressure sensitive keys in response to a received haptics controlsignal corresponding to the given one of the pressure sensitive keyssuch that a first haptics motion is imparted to the given one of thepressure sensitive keys at the first pressure level applied to the givenone of the pressure sensitive keys that is different than a secondhaptics motion that is imparted to the given one of the pressuresensitive keys at the second pressure level applied to the given one ofthe pressure sensitive keys.
 18. The method of claim 17, method furthercomprising providing a haptics key pressure indication signalcorresponding to each given one of the pressure sensitive keys to thehaptics control circuitry from the pressure sensing interface circuitry,the second key pressure indication signal being provided as a digitaloutput bit stream that is representative of the pressure being appliedto the corresponding given one of the pressure sensitive keys during theduration of a given key pressure application event and at the same timethat the pressure sensing interface circuitry provides to a keyboardcontroller that is separate from the haptics control circuitry a digitalkey emulation key pressure indication signal during the duration of thesame given key pressure application event.
 19. The method of claim 17,further comprising providing a keyboard device body that includes thepressure sensing interface circuitry, haptics control circuitry andhaptics actuation circuitry; providing an information handling systemchassis that includes a legacy keyboard key matrix having column/rowintersections coupled to a legacy keyboard controller having no analoginput circuitry and a host system device coupled to the legacy keyboardcontroller; mechanically coupling the keyboard device body as a drop-inkeyboard to the information handling system chassis; and providing eachdigital key emulation key pressure indication signal as a separatealternating open/short digital output signal corresponding to eachpressure sensitive key to column/row intersections of the legacykeyboard key matrix such that the legacy digital keyboard controller isitself coupled between the pressure sensing interface circuitry and theseparate host system device to measure keyboard input for the hostdevice based on received momentary-on digital signals and not based onreceived analog signals.
 20. The method of claim 17, further comprisingproviding the haptics control signal corresponding to each given one ofthe pressure sensitive keys as a selected vibration waveform having atleast one of a vibration intensity or frequency corresponding to thepressure level being applied in real time to the corresponding given oneof the pressure sensitive keys; and using the haptics actuationcircuitry to impart haptics motion according to the selected vibrationwaveform independently to the corresponding given one of the pressuresensitive keys being pressed.
 21. The method of claim 17, furthercomprising: providing a plurality of pressure sensitive keys; providingfrom each of the pressure sensitive keys to the pressure sensinginterface circuitry a respective separate analog output signalrepresentative of the level of pressure being applied to the givenpressure sensitive key; providing a separate respective haptics keypressure indication signal from the pressuring sensing interfacecircuitry to the haptics control circuitry that is representative of atleast two respective different levels of pressure applied to eachindividual one of the pressure sensitive keys, the at least twodifferent levels of pressure comprising at least first and seconddifferent levels of pressure; providing from the haptics controlcircuitry to the haptics actuation circuitry a separate respectivehaptics control signal corresponding to each given one of the pressuresensitive keys based upon each respective received haptics key pressureindication signal; and using the haptics actuation circuitry toseparately and independently impart haptics motion to each of theplurality of pressure sensitive keys with a variable haptics motioncharacteristic based on the applied key pressure level and based on theidentity of the received haptics control signal corresponding to eachgiven one of the pressure sensitive keys such that a first hapticsmotion is imparted to the given one of the pressure sensitive keys atthe first pressure level applied to the given one of the pressuresensitive keys that is different than a second haptics motion that isimparted to the given one of the pressure sensitive keys at the secondpressure level applied to the given one of the pressure sensitive keys.22. The method of claim 17, further comprising: providing a plurality ofpressure sensitive keys; providing from each of the pressure sensitivekeys to the pressure sensing interface circuitry a respective separateanalog output signal representative of the level of pressure beingapplied to the given pressure sensitive key; simultaneously providing asingle common haptics key pressure indication signal to the hapticscontrol circuitry that is representative of at least first and seconddifferent levels of pressure applied to any one of the pressuresensitive keys and simultaneously providing a separate respectivehaptics enable signal to allow actuation of only the haptics actuationcircuitry corresponding to the identity of each given one of thepressure sensitive keys based upon each respective received key pressureindication signal; providing from the haptics control circuitry to allthe haptics actuation circuitry only a single common haptics controlsignal based upon the received single common key pressure indicationsignal; and separately and independently using the single common hapticscontrol signal to impart haptics motion to only those pressure sensitivekeys identified by a corresponding haptics enable signal with a variablehaptics motion characteristic based on the applied key pressure levelrepresented by the received common haptics control signal such that afirst haptics motion is imparted to the given one of the pressuresensitive keys at the first pressure level applied to the given one ofthe pressure sensitive keys that is different than a second hapticsmotion that is imparted to the given one of the pressure sensitive keysat the second pressure level applied to the given one of the pressuresensitive keys.
 23. The method of claim 16, further comprising impartinga variable haptics motion characteristic independently to each given oneof the pressure sensitive keys corresponding to the at least first andsecond different levels of pressure applied in real time to thecorresponding given one of the pressure sensitive keys, the hapticsmotion imparted to each given one of the pressure sensitive keys inresponse to a haptics key pressure indication signal corresponding tothe first level of pressure applied to the corresponding given one ofthe pressure sensitive keys being different than the haptics motionimparted to each given one of the pressure sensitive keys in response toa haptics key pressure indication signal corresponding to the secondlevel of pressure applied to the corresponding given one of the pressuresensitive keys.
 24. The method of claim 16, where the step of providingone or more pressure sensitive keys further comprises providing one ormore pressure sensitive keys that each comprises a keycap and separatehaptics actuation circuitry for the keycap, the separate hapticsactuation circuitry for each given keycap comprising a separate piezotransducer coupled to separately vibrate the given keycap.
 25. Thekeyboard system of claim 13, where the haptics key pressure indicationsignals provided at the first signal output comprise a falling edgetrigger event and a selected waveform address that corresponds to thedesired vibration waveform and current pressure level applied to thegiven key.
 26. A keyboard system, comprising: a plurality of pressuresensitive keys and pressure-sensing digital output circuitry coupledbetween the plurality of pressure sensitive keys and haptics controlcircuitry, the plurality of pressure sensitive keys each beingconfigured to provide to the pressure-sensing digital output circuitry arespective separate analog output signal representative of a level ofpressure being applied to a given pressure sensitive key, and thehaptics control circuitry being coupled between the plurality ofpressure sensitive keys and separate haptics actuation circuitry; and aseparate haptics control switch coupled to control the separate hapticsactuation circuitry for each one of the given plurality of pressuresensitive keys, the haptics control switch being different than thegiven pressure sensitive key and being coupled to receive a separatehaptics enable signal from the pressure-sensing digital output circuitrycorresponding to the given pressure sensitive key; where thepressure-sensing digital output circuitry is configured tosimultaneously provide a single common haptics key pressure indicationsignal to the haptics control circuitry that is representative of atleast two different levels of pressure applied to any one of the givenplurality of pressure sensitive keys and to simultaneously provide aseparate respective haptics enable signal to a given one of the separatehaptics control switches to allow actuation of only the hapticsactuation circuitry corresponding to the identity of the given one ofthe plurality of pressure sensitive keys based upon each respectivereceived haptics key pressure indication signal, the at least twodifferent levels of pressure comprising at least first and seconddifferent levels of pressure; where the haptics control circuitry isconfigured to provide to all of the haptics actuation circuitry only asingle common haptics control signal based upon the received singlecommon key pressure indication signal; and where the separate hapticscontrol switch coupled to control the separate haptics actuationcircuitry corresponding to each one of the given plurality of pressuresensitive keys is configured to allow and disallow application of thesingle common haptics control signal to the haptics actuation circuitrysuch that the haptics actuation circuitry is configured to separatelyand independently use the single common haptics control signal to imparthaptics motion to only a pressure sensitive key identified by acorresponding haptics enable signal with a variable haptics motioncharacteristic based on the applied key pressure level represented bythe received common haptics control signal such that a first hapticsmotion is imparted to each identified pressure sensitive key at thefirst pressure level applied to the identified pressure sensitive keythat is different than a second haptics motion that is imparted to theidentified pressure sensitive key at the second pressure level appliedto the identified pressure sensitive keys.
 27. A method of impartinghaptics motion, comprising: providing a plurality of pressure sensitivekeys; providing haptics control circuitry and separate haptics actuationcircuitry corresponding to each one of the plurality of pressuresensitive keys, the haptics control circuitry being coupled between theplurality of pressure sensitive keys and the haptics actuationcircuitry; providing pressure-sensing digital circuitry coupled betweenthe plurality of pressure sensitive keys and the haptics controlcircuitry; providing a separate respective haptics control switchcoupled to control the separate haptics actuation circuitrycorresponding to for each individual one of the plurality of pressuresensitive keys, the haptics control switch being different for eachgiven pressure sensitive key and being coupled to receive a separatehaptics enable signal from the pressure-sensing digital output circuitrycorresponding to the individual given pressure sensitive key; producingan analog output signal for each given one of the plurality of pressuresensitive keys when depressed during a key pressure application event ofa given pressure level by a user, the analog output signal beingrepresentative of the level of pressure applied to the given pressuresensitive key by the user; receiving the analog output signal from eachgiven one of the plurality of pressure sensitive keys in thepressure-sensing digital output interface circuitry; providing a singlecommon key pressure indication signal from the pressure-sensing digitaloutput circuitry, the single common key pressure indication single beingbased upon a corresponding received analog output signal and beingrepresentative of one of at least two respective different levels ofpressure applied to any given one of the plurality of pressure sensitivekeys that is currently pressed, the at least two different levels ofpressure comprising at least first and second different levels ofpressure; simultaneously providing a separate respective haptics enablesignal to a given one of the individual haptics control switches toallow actuation of only the separate haptics actuation circuitrycorresponding to the identity of the given one of the plurality ofpressure sensitive keys currently being pressed based upon the receivedanalog output signal; receiving the single common key pressureindication signal in the haptics control circuitry and providing fromthe haptics control circuitry, a single common haptics control signalbased upon the received single common key pressure indication signal;and using a the respective haptics control switch coupled to thepressure-sensing digital output circuitry and the separate hapticsactuation circuitry corresponding to each individual one of theplurality of pressure sensitive keys to allow and disallow applicationof the single common haptics control signal to the haptics actuationcircuitry of a corresponding one of the plurality of the pressuresensitive keys based on the respective presence and absence of a hapticsenable signal selectively applied by the pressure sensing digital outputcircuitry to the given haptics control switch to allow the single commonhaptics control signal to be selectively used to impart haptics motionsto multiple separate and different haptics actuation circuitriescorresponding to multiple plurality of pressure sensitive keys.